Wellington, New Zealand – A powerful 7.3 magnitude earthquake struck just off the coast of Vanuatu on Tuesday, causing widespread destruction in the South Pacific island nation. At least six people reportedly died. Injured people arrived at hospitals and among the badly damaged buildings in the capital Port Vila was one housing the US embassy.

A tsunami warning was lifted less than two hours after the quake. With communications still broken hours later and official information scarce, witness accounts of victims emerged on social media and through patchy phone calls.

Katie Greenwood, the head of the Pacific division of the International Federation of the Red Cross, said in a social media post that at least six people were dead and many more were injured.

The quake struck just before 1 p.m. at a depth of 35 miles and was centered 18 miles west of Port Vila, the largest city in Vanuatu – a group of 80 islands home to about 330,000 people. This was followed by a magnitude 5.5 aftershock near the same location, with shaking continuing throughout the afternoon and evening.

It was not immediately clear how much damage was caused, with phone lines and government websites down, but the IFRC’s Greenwood said several buildings collapsed and the hospital in the capital was damaged.

Doctors were working “as quickly as they could” in a triage center outside the emergency room, journalist Dan McGarry told The Associated Press, adding that the country was not well equipped to deal with a mass casualty event. Videos shared by the Vanuatu Broadcasting and Television Corporation showed crowds outside the hospital.

In the first official information released by Vanuatu’s government, the Geohazards Authority said on social media that its monitoring systems remained offline due to power outages. Residents have been urged to stay away from the coast for at least 24 hours until tsunami and earthquake monitoring systems are operational again.

A video posted on social media appeared to show crumpled buildings in Port Vila, including one that had collapsed to its lower floors, and cars parked on the street below. Amanda Laithwaite said her husband was among a group of rescuers who tried to move the roof of the three-story building because they believed people were trapped inside, but without special machinery they made slow progress.

A building that housed a number of diplomatic missions in Port Vila, including those of the US, Britain, France and New Zealand, was significantly damaged, several of its tenants said, but the US Embassy said this in a statement on its Facebook page posted message saying staff were safe, although the building was closed until further notice.

The US mission only opened in July, as part of a broader US push to expand its presence in the Pacific to counter this China’s growing influence about the governments in the region.

A video posted on social media showed the building had some damage, including dented windows and debris that had fallen from the walls to the floor.

French news agency AFP said its photos showed the ground floor of the diplomatic building completely flattened. The ground floor “no longer exists,” Vanuatu’s Michael Thompson told AFP by satellite phone after posting images of the destruction on social media. “It’s just completely flat. The top three floors are still holding but have sunk.”

“There are people in the city’s buildings. There were bodies there when we walked by,” Thompson said. The quake also brought down at least two bridges and caused other buildings to collapse, he said.

McGarry, the journalist, said a “massive landslide” at the international shipping terminal would likely hamper the country’s recovery. The airport’s runway was also damaged, he said.

Because of Vanuatu’s location in a subduction zone – where the Indo-Australian tectonic plate moves beneath the Pacific plate – earthquakes of magnitude greater than 6 are not uncommon and the country’s buildings are designed to withstand earthquake damage.

“I think it could have been worse,” McGarry said. But this was “by far” the worst thing he had experienced in his 21 years in Vanuatu, he said.

Port Vila airport could not be contacted on Tuesday, but flight tracking sites suggested all flights had been suspended. Some airlines in Australia and the Pacific said they had canceled or paused flights scheduled for Wednesday and were awaiting news on the status of the airport.

Australian Foreign Minister Penny Wong told reporters her country would provide any assistance needed. New Zealand Foreign Minister Winston Peters said 45 New Zealanders were registered in Vanuatu and his government was “deeply concerned” about the situation there.

Vanuatu has been led by four prime ministers in four years and is due to go to early elections in January. In November, Prime Minister Charlot Salwai called on President Nikenike Vurobaravu to dissolve parliament so that he would not face a vote of no confidence like his recent predecessors.