A UN agency has released a set of satellite images that offer a glimpse of the damage from Saturday's massive eruption of an underwater volcano in the South Pacific.

The eruption occurred about 65 kilometers north of Tonga's capital, Nuku'alofa. Tsunamis up to about 80 centimeters high were observed in Tonga.

The scale of damage is still unclear, as telephone and internet communications in the area are significantly limited.

One of the 22 pictures released by the UN Satellite Centre on Monday shows a coastal area of Tongatapu Island, where Nuku'alofa is located. The image shows traces of tsunami that swept as far as 100 meters inland.

A comparison of that picture with another one taken prior to the eruption suggests two buildings in the area may have suffered damage.

Another photo, taken on December 8, shows a 285-hectare volcanic island.

But the island is invisible in a picture of the same area taken on Sunday, suggesting that most of the land has likely vanished following the eruption.

Officials said the images also show a large swath of Tonga blanketed in ash.