Houses in Iceland's Hafnarfjordur are seen as smoke billows in the distance, the night sky turned orange by lava from an volcanic eruption
Houses in Iceland's Hafnarfjordur are seen as smoke billows in the distance, the night sky turned orange by lava from an volcanic eruption AFP

A volcanic eruption began Monday night in Iceland, south of the capital Reykjavik, following an earthquake swarm, Iceland's Meteorological Office said.

For weeks, the Nordic country has been on high alert for a potential eruption at any moment after a period of intense seismic activity on the southwest peninsula, which last month prompted evacuation orders.

"At 22:17 this evening, a volcanic eruption began north of Grindavik on the Reykjanes peninsula," the IMO said, adding that it could be seen from nearby webcams.

The live-streamed footage of the eruption showed large jets of glowing orange lava spewing into the night sky, surrounded by billowing red smoke.

"A Coast Guard helicopter will take off shortly to confirm the exact location and size of the eruption," the IMO said.

In November, thousands of small earthquakes rattled the region south of Reykjavik.

The roughly 4,000 residents of Grindavik, a fishing port around 40 kilometres (25 miles) from the capital, were evacuated on November 11 after officials determined a tunnel of magma was shifting beneath them, considered a precursor to an eruption.

Residents told AFP the seismic activity had damaged roads and buildings.

Since then, they have only been allowed to visit their homes during certain daylight hours.

Authorities have organised occasional trips into the village, escorting those with homes in the most perilous parts to rescue everything from cherished pets to photo albums, furniture and clothing.

Volcanic eruptions are not uncommon in Iceland, which is home to 33 active volcano systems, the highest number in Europe.

But the Reykjanes peninsula had not experienced an eruption for eight centuries until 2021.

Since then, three eruptions have struck -- all in remote, uninhabited areas -- and volcanologists say this could be the start of a new era of activity in the region.

Previous eruptions near the Fagradalsfjall volcano on the Reykjanes peninsula took place in 2021, 2022 and earlier this year.

In 2010, the eruption of Iceland's long-dormant Eyjafjallajokull volcano -- an ice-capped volcano more than 1,660 metres tall -- shot huge amounts of ash into the atmosphere. That massive, explosive eruption was not fatal, but forced the cancellation of around 100,000 flights and left more than 10 million travellers stranded.

Situated in the North Atlantic, Iceland straddles the Mid-Atlantic Ridge, a crack in the ocean floor separating the Eurasian and North American tectonic plates.