Unita said it had invited the politicians, including Tanzanian opposition leader Tundu Lissu, Mozambique’s Venancio Mondlane and Botswana’s former President Ian Khama, to a summit on democracy.

“The action of the Angolan government to prevent us from entering Angola is inexplicable and unacceptable,” Lissu said on X.

The BBC has asked the Angolan government to comment.

But according to a source from the Migration and Aliens Service (SME), “the expulsion was due to irregularities in the visa procedure, which prevented Mondlane and 13 other members of his entourage from entering Angolan territory”.

At least 20 leaders and representatives from various political parties across Africa were denied entry, said Lissu.

“The government of this country is ruling a dictatorship while pretending that Angola is a democratic country,” he said.

Kenyan senator Edwin Sifuna, from the opposition Orange Democratic Movement, said on X he was among those denied entry into Angola.

Others included Colombia’s former President Andres Pastrana and Zanzibar’s first Vice-President Othman Masoud Othman.

Tomas Viera Mario, a Mozambican political analyst, told the BBC the move was “strange” as Angola’s President Joao Lourenco has positioned himself as a kind of mediator on the continent.

Lourenco is currently the chair of the African Union (AU), and is hosting peace talks over the DR Congo conflict next week.

Mr Mario added that barring these figures showed “total contempt and “little respect” for the pan-African spirit of the AU.

All the deported leaders were part of a delegation invited by Unita to participate in a political event in Benguela province.

Unita lawmaker Nelito da Costa Ekwiki also condemned the decision not to allow them entry to the country.

The Angolan government has long been accused of shutting down dissent in order to maintain its hold on power.

In a landmark case, the court handed the company’s British former chief operating officer Mike Wainwright, who has also competed as a racing driver, a 32-month jail sentence and fined the company $148m (£119m).

This is the first time an entire company has been charged by Switzerland’s highest court, and bribery convictions of senior staff are rare.

Trafigura’s lawyers said the company and Wainwright intended to appeal against the verdict, so the former executive was not jailed immediately.

The case against Trafigura has had all the elements of a financial thriller: millions of dollars, shady middlemen and a chain of shell companies located in offshore havens like the Virgin Islands.

Trafigura’s strategy, the court heard, was to set up a complex payment web, through which an official with Angola’s state oil company was paid almost $5m (£4.02m; €4.81) between 2009 and 2011.

Documents presented to the court by Swiss prosecutors showed payments authorised on Trafigura’s own headed notepaper.

The strategy appeared to work: over the next few years, the court heard, Angola signed contracts with Trafigura worth almost $144m (£115.93; €138.56).

Trafigura, whose lawyers appeared bullish before the verdict, denied bribery. The company said its own compliance and anti-corruption measures had been independently assessed and found to be excellent.

But the sheer weight of the evidence – which included dozens of documents, emails and memos – revealed a different picture: strict anti-corruption measures on paper but an intricate structure set up to evade those measures in reality. At the heart of it sat a middleman named “Mr Non-Compliant” in an anonymous Geneva office.

The case will send a chill through commodity brokers worldwide but especially in Geneva, where Trafigura and many other commodity trading houses are headquartered.

In an eerie coincidence, the night before the verdict was delivered, a fire broke out at the five star Hotel des Bergues – where, court documents showed, an Angolan official stayed at the expense of Trafigura in 2008.

Swiss federal prosecutors hope the case will be a symbol that the old ways of doing business are finally over.

They brought the charges to Switzerland’s highest court, reserved for the worst crimes, such as terrorist offences.

Trafigura now faces a large fine and Wainwright, who was in court for the verdict and denied the charges, was told he must serve at least one year of his 32 month sentence in jail.

However, he was not immediately detained, pending the appeal he intends to lodge.

“Contrary to what we expected, the summit will no longer be held today,” the presidency’s media officer Mario Jorge told journalists on Sunday, without elaborating on why the meeting was cancelled at the last minute.

Angolan President Joao Lourenco – the African Union mediator to end the conflict – was meeting alone with DRC leader Felix Tshisekedi, Jorge said.

Rwandan President Paul Kagame had been expected at the meeting but it was not clear if he was in Angola.

The DRC presidency said in a statement that the meeting was cancelled because the Rwandan delegation refused to take part.

Rwanda’s foreign ministry said that a lack of consensus over direct talks between the DRC and a rebel group meant that it would not have been possible for a deal to be signed on Sunday.

There had been hopes the talks would reach an agreement to end the conflict in the eastern DRC, where the M23 fighter group – which the DRC and the UN say is backed by Rwanda – has seized swaths of territory, displacing thousands and triggering a major humanitarian crisis.

Before the talks, fighting intensified between the DRC army and the M23 rebel group on Friday.

The DRC’s army had accused M23 of killing 12 civilians earlier this week in villages of the Lubero territory in the eastern province of North Kivu.

An M23 spokesperson, however, denied the accusation, discrediting it as “propaganda” from the DRC government.

M23 is one of about 100 armed groups that have been vying for a foothold in the mineral-rich eastern part of DRC near the border with Rwanda.

The conflict there has created one of the world’s largest humanitarian crises, with more than seven million people displaced.

Rwanda denies that it backs the M23, but in February admitted that it has troops and missile systems in eastern DRC to safeguard its security, pointing to a buildup of DRC forces near the border.

According to a UN expert group report, 3,000 to 4,000 Rwanda Defence Force (RDF) members are fighting alongside the M23 in DRC.

Last month, the DRC and Rwanda’s foreign ministers agreed on the terms and conditions of the disengagement of Rwandan forces in eastern DRC.

In July, DRC signed a ceasefire with M23 that came into effect in August, but fighting has resumed since.

Earlier this month, the United States said it was “gravely concerned” by ceasefire violations by M23 rebels.

Aline Kasereka, a mother of six living in the DRC’s town of Lubero, approximately 50km (30 miles) from the villages where the fighting took place this week, said the peace talks between the two neighbouring countries are urgently needed.

“We are tired of the war, every day we move, we do not know in which country we are any more,” Kasereka told The Associated Press news agency.

Discussions at the presidential palace in the capital, Luanda, will be on security and trade.

The US government is backing a new 1,300km (810-mile) railway project linking an Angolan port with mining areas in neighbouring Democratic Republic of Congo and Zambia.

The visit to oil-rich Angola is part of a US effort to focus more on trade and investment in Africa, in what some analysts see as a counter to China’s influence on the continent.

In his first and only trip to Africa during his presidency, Biden’s choice of Angola is significant and it signals a dramatic improvement in relations between the two nations.

Welcoming the US president to the country, Lourenço described the visit as a turning point in US-Angola relations.

“I’m deeply proud of everything we have done together to transform our partnership thus far,” Biden said in response.

Angola was firmly in the political orbit of China and Russia after independence from Portuguese colonial rule in 1975, but since taking power in 2017, Lourenço has steered it towards closer relations with the US.

Later on Tuesday Biden is due to visit a slavery museum. More than four million slaves were forcibly sent from this region of Africa to the Americas.

“Together, the United States and Angola acknowledge the past horrors of slavery and its legacy, while looking forward to a bright future of continually deepening collaboration between our nations,” the White House said in a statement on Monday.

Biden is set to arrive in the Angolan capital, Luanda, on Monday, after a brief stop in the West African nation of Cape Verde. The two-day trip to Angola, many analysts say, represents a final, desperate attempt to fulfil a promise Biden made long ago, and counter China’s expanding influence on the continent.

The anticipated visit, which was pushed back from October due to Hurricane Milton, will see Biden visit the Lobito Port, which is at the heart of US trade relations with Angola. There, he will assess an ongoing critical minerals infrastructure project that is set to see vast supplies of cobalt and copper delivered to the West.

Here’s what to know about Biden’s Africa visit and why Lobito is important:

Analysts say Biden’s failure to visit any African country – except Egypt for COP27 in November 2022 – until now shows that his administration has not prioritised the continent.

Biden first promised to visit Africa in December 2022, two years into his presidency – which some note was already too late.

He made the promise at a US-Africa leaders summit in Washington, where 49 African leaders gathered. The US “is all in on Africa and all in with Africa”, Biden declared at the time. He also announced a support package of $55bn to the African Union.

The Biden administration has hosted several African leaders in the White House, but the promised visit never materialised – until now.

“Presidential trips to Africa are rare enough that they always matter,” Cameron Hudson, a senior Africa analyst at the US-based Center for Strategic and International Studies said.

“This one would matter less coming as it does at the very end of a lame-duck presidency. Ironically, [an Africa trip] probably matters more to Biden, who is searching to establish a legacy in Africa…than for Africa, which is already preparing for his successor,” Hudson added.

Africa’s significant natural resources, rapidly growing population of 1.3 billion, and sizeable voting power in the United Nations – with 54 country votes – make the continent an increasingly important strategic player.

US influence on the continent has been waning for years, even as China and Russia have strengthened their presence in several countries.

China has since 2013 overtaken the US to become Africa’s largest trade partner. This year, the US lost a major spy base in the West African nation of Niger, and its army got kicked out of Chad. That has left it struggling to find a military foothold in the Sahel region which has become a hotspot of violence by a range of armed groups.

In 2022, the White House released an ambitious Africa strategy document that shifted from the first Trump administration’s focus on trade relations.

Rather, the document promised, the US would push for Africa to have leadership roles at international platforms, including permanent seats on the United Nations Security Council and membership of the G20. Analysts lauded the approach as “modern” and “ambitious” at the time but enthusiasm for it quickly faded as little action followed.

Several top officials, including Vice President Kamala Harris and Secretary of State Antony Blinken, have visited African countries at various times.

Meanwhile, Biden found time to travel elsewhere. He has visited the United Kingdom alone five times, apart from numerous other visits to Europe, the Middle East, Asia and Latin America.In contrast, President Xi Jinping of China and Russia’s President Vladimir Putin have visited African countries at least twice as heads of state.

The visit to Luanda will see Biden focus on an $800m US-backed railway project in the Lobito Corridor. The passage is a strategic trade route that connects the resource-rich Democratic Republic of Congo (DRC) and Zambia to Angola, which hosts the port of Lobito, located on the Atlantic Ocean.

Funded largely by the US and the European Union, the Lobito Atlantic Railway project will see an existing rail network in the Lobito Corridor upgraded. That would allow for the faster export of cobalt and copper, amongst other minerals, mined from the DRC’s Kolwezi mining town, to the West.

The DRC is one of the world’s largest producers of copper and cobalt. The minerals are key components of batteries that power electric vehicles, which the US and EU are eager to develop more of as demand for clean energy supply chains grows.

Washington has provided a $550m loan to start the project. The African Development Bank and the Africa Finance Corporation are also involved.

The rail line is about 1300km (800 miles) long and will likely see extensions into mineral-rich regions in Zambia. Portuguese company Trafigura is leading a three-company consortium that will operate the railway for 30 years under a concession agreement. In August, the company said it shipped the first container of minerals to the US via the Lobito Port.

Analysts say the US faces challenges in the corridor. China has eyes on the region, too, and has already locked in much of the minerals that would theoretically be sold to Western countries within its huge Belt and Road Initiative, notes researcher Wala Chabala in a paper for the Berlin-based think tank, Africa Policy Research Institute.

“Not only are the Chinese ubiquitously present on the African continent, but China is already far ahead in building supply chains for cobalt, lithium and several other essential metals and minerals,” Chabala wrote.

In September, China’s state engineering corporation signed a concession agreement to operate the Tanzania-Zambia Railway Authority (TAZARA), another railway line in the corridor that links central Zambia to the port of Dar-es-Salaam in Tanzania.

US officials say the visit is meant to highlight the close ties between Angola and the US.

At present, Luanda is also playing a lead role in mediating a spat between the DRC and Rwanda, concerning ongoing violence in eastern Congo.

Angola was, until a few years ago, a heavy borrower from China. It has also been historically close to Russia: During Angola’s 27-year civil war, the US and the former Soviet Union backed rival sides, leading to cold ties between Luanda and Washington.

However, the government of President Joao Lourenco, which has been in place since 2017, has favoured stronger ties with Washington. The two countries have deepened trade relations and by 2023, US-Angola trade totalled approximately $1.77bn.

Angola is the US’s fourth-largest trade partner in sub-Saharan Africa.

In 2021, and more recently, in November 2023, Biden hosted President Lourenco at the White House.

However, analysts say Washington’s view of Lourenco’s government ignores alleged human rights violations under his watch. Lourenco is unpopular amongst many Angolans due to high living costs, corruption, and mounting crackdowns on dissent. In June, authorities opened fire on protesters angry at inflation, killing eight people in the central Huambo province. Several others were arrested in cities across the country.

 Analysts say Biden’s refusal to acknowledge those concerns over alleged rights abuses is a stain on his legacy.

“Many observers believe that Biden’s visit may inadvertently embolden an unpopular president,” said Florindo Chivucute, director of Friends of Angola, a group advocating for stronger democratic values in Angola and based in Luanda and Washington, DC.

“While the US lags behind China in terms of trade and political influence in Angola, it should not compromise its core values of democracy and human rights in an attempt to catch up,” he said.

While President Biden has finally fulfilled his promise to visit Africa, his administration hasn’t been able to accomplish some of the other goals it set for itself.

The African Union was admitted as a permanent member of the G20 in September 2023. However, no African country is still a permanent member of the UNSC.

In September 2024, US Ambassador to the UN Linda Thomas-Greenfield announced that her country would support two permanent UNSC seats for Africa. However, she warned that those seats would not have veto power, a position that many analysts criticised because it would set up a two-tier system – one for UNSC members with vetoes, and the second for those without that power.

A Trump presidency, meanwhile, is likely to focus only on trade relations, as it did the first time, experts say.

The incoming administration will likely want to compete with Chinese and Russian influence, and land access to critical minerals, Tibor Nagy, a top envoy to Africa under the last Trump administration, told the Reuters news agency.

There, at least, projects like the Lobito Railway could see sustained US investment. “This checks both boxes,” Nagy said, referring to the railway project.