The crash happened early on Saturday about 5km (3 miles) from the south-western city of Uyuni.

One of the drivers was receiving intensive care while the other was in a stable condition, police commander Wilson Flores said.

Images published in Bolivian media showed a badly damaged coach with its bodywork ripped off and luggage scattered on the roadside.

The buses collided on the route between Uyuni and Colchani in Bolivia’s Potosí department after a “lane invasion”, local media reported.

One bus was travelling to the western city of Oruro, where Oruro Carnival – one of Latin America’s largest festivals – was taking place.

The vehicles were recovered by 10:00 local time (14:00 GMT) and those injured were taken to hospitals in both Oruro and Potosí.

Those who died have not been identified and the condition of the injured is yet to be determined.

According to local media, Cdr Flores said police were awaiting the results of alcohol tests taken by the drivers.

Deadly traffic accidents are common in Bolivia. More than 30 people were killed in February when a bus plunged almost 800m (2625 ft) into a ravine between the cities of Potosí and Oruro.

In January, 19 people were killed when another bus came off a road in the same region, also near Potosí.

An average of 1,400 people die in road accidents every year in the country of about 12 million inhabitants, according to government data.

The vehicle plunged almost 800m (2625 ft) into a ravine in the southwestern district of Yocalla, an officer said.

Fourteen people were also injured, including four children, an official from a local hospital said in a video.

Bolivia has notoriously dangerous roads, particularly in mountainous areas.

The accident happened between the cities of Potosí and Oruro, police said.

Officials believe that the crash could have been caused by speeding, with the driver “unable” to control the bus, police colonel Victor Benavides told the AFP news agency.

This is believed to be the most serious road accident reported in the South American country so far this year.

Local news outlet Unitel reported that several of those injured were in a serious condition.

Deadly road accidents are common in Bolivia.

Last month, 19 people were killed when another bus came off a road, also near Potosí.

Road accidents kill an average of 1,400 people every year in the country of about 12 million inhabitants, according to government data.

Maximiliano Dávila, also known as “Macho”, is accused of facilitating cocaine smuggling to the US during his time as the head of Bolivia’s anti-narcotics agency.

His extradition, which took place on Thursday, was approved by Bolivia’s Supreme Court in late November. He denies any wrongdoing.

Dávila had been imprisoned in Bolivia on corruption charges since February 2022.

That same month, US officials unsealed an indictment accusing the 60-year-old of cocaine trafficking, and a related weapons charge.

The US Department of State alleges Dávila was involved in narcotics trafficking before and during his time as director of the Bolivian Special Forces for the Fight Against Drug Trafficking (FELCN).

It says Dávila exploited his position to “safeguard aircraft used to transport cocaine to third countries, for subsequent distribution in the United States”.

If convicted, he faces a minimum sentence of 10 years in prison and a maximum term of life in prison, according to US documents.

The state department in 2022 offered a reward of up to $5m (£4m) for information that could lead to his conviction.

Dávila was FELCN director under former President Evo Morales, who governed Bolivia from 2006 to 2019.

Shortly after Dávila’s extradition, Morales criticised the move and said “Bolivia is once again a US Colony”, in a post on his X account.”Bolivians are handed over to the North American Empire, violating international agreements, without first being tried in their homeland where they supposedly committed crimes”, he added.

In 2008, Morales expelled the US ambassador and the Drug Enforcement Administration (DEA) from Bolivia for allegedly conspiring against his government.

Morales himself is under investigation for alleged statutory rape and human trafficking, which he denies. His supporters recently staged blockades around the country for weeks demanding the end of the investigation against him.

In November, he shared a video of his car being shot at, in what he called an “assassination attempt” against him.

The Bolivian government rejected Morales’ claims that it was behind the attempt on his life.