Two hundred others are being treated for injuries, with powerful aftershocks from the 7.3-magnitude tremor reported overnight.

The earthquake damaged buildings, including the embassies of the US, France, the UK and New Zealand. It also cut power and mobile services.

Vanuatu police say a seven-day state of emergency has been declared to limit the movement of the public while search and relief operations are underway.

Four of the fatalities died at hospital in the capital city of Port Vila, the government said. Six were from a landslide, while four were from a collapsed building, where the toll was expected to rise further.

Two of the fatalities were Chinese nationals, Chinese Ambassador to Vanuatu Li Minggang told state media.

An estimated 116,000 people could be affected by the worst impacts of the quake, the UN Office for the Coordination of Humanitarian Affairs said.

Neighbouring Australia will send teams to assist in the search and rescue effort, Deputy Prime Minister Richard Marles told ABC News on Wednesday. The US and France have also pledged aid.

Photos shared by Vanuatu Police on Facebook showed rescuers sifting through rubble by hand and crawling under the floors of collapsed buildings.

At least 10 buildings in Port Vila sustained “major structural damage”, the government’s disaster management office said.

From the rubble of one three-storey building, rescuers heard the voices of at least three people, Vanuatu resident Michael Thompson told AFP news agency.

Thompson said rescuers used “everything we can get our hands on”, including jack hammers, grinders and concrete saws, to rescue people.

Images from state broadcaster VBTC showed many businesses in Port Vila closed on Wednesday, with debris scattered on the sidewalk and some roads cracked.

Some people could be seen looking for essential supplies.

The earthquake struck at 12:47 local time (01:47 GMT) on Tuesday and triggered a brief tsunami warning.

Vanuatu, a low-lying archipelago of some 80 islands in the South Pacific, is located west of Fiji and thousands of kilometres east of northern Australia.

The nation sits in a seismically active area, and is susceptible to frequent large earthquakes and other natural disasters.

Power and mobile networks across the country have been cut off and the full extent of the damage still remains unclear, but there are unconfirmed reports of at least one death.

Dan McGarry, a journalist living in Port Vila, said he saw “several people who were visibly, seriously injured” outside the hospital’s emergency department.Vanuatu is prone to earthquakes, but Mr McGarry said that the earthquake, which struck at 12:47 local time (01:47 GMT), felt like “the biggest one… in more than 20 years”.

“Emergency services are going to be busy for a while. We have limited equipment and capabilities here [in Vanuatu]”, said Mr McGarry, adding that police at the Vila Central Hospital told him that one person has died, and that he expects the death toll to rise.

One of the clips from state broadcaster VBTC’s Facebook page showed dozens of people outside the Vila Central Hospital, many lying on hospital gurneys awaiting treatment.

Michael Thompson, director of the Vanuatu Jungle Zipline adventure company, told AFP news agency that he had seen bodies lying in the streets.

“There’s multiple buildings that have come down around town. There’s a big rescue operation on the way to clear out people who are possibly alive in the building,” Mr Thompson said, in a separate video posted to Facebook.

“I thought the ceiling [of our house] was going to come right down, Mr Thompson’s wife Amanda told the BBC.

“We often have earthquakes here but not like this.. The house has giant cracks all through it, sliding glass doors are smashed.

“We are feeling a lot of after shakes now, each one nervously makes us as we run out the door to open air,” she said.

However Mr McGarry added that the latest disaster was something the people of Vanuatu would “get through”.

“People in Vanuatu deal with natural disasters on a yearly basis. It’s in our blood. We’ll get through this as well, although not without some suffering,” he said.

Vanuatu, a low-lying archipelago of some 80 islands in the South Pacific, is located west of Fiji and thousands of kilometres east of northern Australia.

The nation sits in a seismically active area, and is susceptible to frequent large earthquakes and other natural disasters.

The United States Embassy, the British High Commission, the French Embassy and the New Zealand High Commission were among the damaged buildings, with all of them being housed in the same complex.

US officials said the building sustained “considerable damage” and would be closed until further notice. All staff in the building had safely evacuated, they added.Separately, Australian carrier Jetstar cancelled a flight scheduled for Wednesday morning from Sydney to Port Vila, citing “earthquake activity in Vanuatu and reports of possible damage to Port Vila airport infrastructure”.

The United States Geological Survey reported at least four aftershocks around Port Vila – with magnitudes ranging from 4.7 to 5.5 – in the two hours after the first earthquake. The first quake hit at a depth of 10km (6.2mi).

Authorities in neighbouring New Zealand and Australia said there was no tsunami threat for their countries.

Australia also said it “stands ready to support Vanuatu as the extent of the damage is assessed”.

“Vanuatu is family and we will always be there in times of need,” Foreign Minister Penny Wong wrote on X.

New Zealand said it is “deeply concerned” and is monitoring the situation. “Our thoughts are with the people and authorities of Vanuatu,” said Foreign Minister Winston Peters.