The volcanic eruption under the sea in Tonga has been going on for weeks, but the activity increased explosively during the night until Saturday Swedish time.
The eruption has, among other things, caused a large ash cloud to settle over Tonga.
The country has therefore lost contact with the outside world.
One of the victims is the previously known Olympian Pita Taufatofua.
Became famous in 2016
He made himself known when he appeared at the 2016 Olympic Games inauguration, as a representative of Tonga, with an oiled and bare torso.
The 38-year-old competed in taekwondo and was eliminated in the first round.
Taufatofua lives in Australia but has his family in Tonga.
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Olympic profile Pita Taufatofua has not heard from her family since the volcanic eruption in Tonga.
Photo: TT / Bildbyrån
"All communication from Tongo is still down after the outbreak.
I still have not heard anything from my father or family ", he writes on his Instagram.
Difficult to assess injuries
Taufatofua writes that his family lives near the water on an island in Ha'apai.
The damage in Tonga is still difficult to assess, reports TT.
No one is said to have been killed or injured.