Every home on one of Tonga’s small outer islands was destroyed in the massive volcanic eruption and tsunami, with three people so far confirmed dead, the government says in its first update since the disaster hit.

With communications severely hampered by an undersea cable being severed, information on the scale of the devastation after Saturday’s eruption – causing waves up to 15 metres high – has so far mostly come from reconnaissance aircraft.

But the office of Prime Minister Siaosi Sovaleni said in a statement that every home on Mango island, where about 50 people live, had been destroyed, only two houses remained on Fonoifua, and Namuka island had suffered extensive damage in the “unprecedented disaster”.

FIRST OFFICIAL UPDATE FOLLOWING THE VOLCANIC ERUPTION FROM THE GOVERNMENT OF TONGA 🇹🇴 pic.twitter.com/fX3KPlKx2E

— Consulate of the Kingdom of Tonga (@ConsulateKoT) January 18, 2022

Tonga’s deputy head of mission in Australia, Curtis Tu’ihalangingie, earlier said pictures taken by the New Zealand Defence Force showed “alarming” scenes of a village destroyed on Mango and buildings missing on Atata island, which is closest to the volcano.

“People panic, people run and get injuries. Possibly there will be more deaths and we just pray that is not the case,” Mr Tu’ihalangingie told Reuters.

Mr Sovaleni’s office said a 65-year-old woman on Mango Island and a 49-year-old man on Nomuka Island had been killed, in addition to a British woman whose death was confirmed on Monday.

• Read more: Woman died rescuing dogs from Tonga disaster

Several injuries were also reported.

The United Nations said on Monday a distress signal was detected in the outlying Ha’apai islands, where Mango is located.

Tsunami waves reaching up to 15 metres had hit the Ha’apia island group and the west coast of Tonga’s main island, Tongatapu, the prime minister’s office said.

On the western coast of the main island, 56 houses were completely or seriously damaged and residents moved to evacuation centres.

Mango is about 70 kilometres from the Hunga Tonga-Hunga Ha’apai volcano, which sent tsunami waves across the Pacific Ocean when it erupted with a blast heard 2300 kilometres away in New Zealand.

A search-and-rescue operation began on Sunday for Atata island, which has a population of about 100.

“Challenges to sea and air transportation remain due to damage sustained by the wharves and the ash that is covering the runways,” the government said.

The office said some limited communications had been made with satellite phones but some areas remained cut off.

The Tongan navy had deployed with health teams and water, food and tents to the Ha’apai islands, with more aid sent on Tuesday due to the severity of the damage observed on Mango, Fonoifua and Namuka islands, it said.

The NZDF images, posted on a Facebook site and confirmed by Mr Tu’ihalangingie, showed tarpaulins being used as shelter on Mango island.

Tonga is expected to issue formal requests for aid soon. In the meantime, New Zealand said two ships, HMNZS Wellington and HMNZS Aotearoa, had set off with water supplies, survey teams and a helicopter.

Volcanic ash has blanketed rooftops and vegetation in Tonga. Photo: NZ Defence Force/AP

Australia’s Minister for the Pacific Zed Seselja said Tongan officials were hoping to evacuate people from the isolated, low-lying Ha’apai islands group and other outer islands where conditions were “very tough, we understand, with many houses being destroyed in the tsunami”.

British charity worker Angela Glover, 50, was killed in the tsunami as she tried to save the dogs she looked after at a shelter, her brother said.

Ms Glover’s brother, Nick Eleini, said he managed to speak to her “guilt-ridden” husband, James Glover, who survived the incident, on Monday night after he found her body.

The island faces issues with communication as a result of an underwater cable being severed during the blast and tsunami.

Victim Angela Glover, left, lived with her husband James, right, in Tonga. Photo: Facebook

“He’s been able to communicate with us via satellite phone from the British Embassy. He’s safe, he has all his basic needs covered, he has shelter, food, water and money,” Mr Eleini told BBC Breakfast:

“I don’t believe he sustained any serious injuries. He is naturally just shattered and guilt-ridden as to the events that took place. He’s quite naturally blaming himself for not being able to save Angela.

“It doesn’t matter how many times we tell him he has nothing to reproach himself for. He is carrying an incredible burden of guilt at the moment.”

Mr Eleini said Mr Glover told him the damage to the island after the eruption was bad, and the full extent would be “quite apparent” in coming days.

“I think there is going to be a major humanitarian disaster unfolding there. I hope not, but there’s a lot of outlying islands in Tonga that haven’t been reached that people still need to get to,” he said.

“As far as the main island where James and Angela were living, I believe is quite flat, so the wave from the tsunami would have extended quite a way over the land, particularly on that north and west coast.

“A lot of the infrastructure is above ground; that has probably been completely destroyed.”

South Pacific Animal Welfare, which worked with Ms Glover helping to rescue dogs in Tonga, said the news of her death was “heart-breaking”.

-AAP