REYKJAVIK, Iceland (AP) — Iceland’s president said the country is battling “enormous forces of nature” after molten lava from a volcano in the island’s southwest consumed several homes in the evacuated town of Grindavik.

Scientists said Monday the eruption appeared to be subsiding, but it was too early to declare the danger over. The Icelandic Meteorological Office said: “It is difficult to estimate how long this outbreak will last.”

President Gudni Th. Johannesson said in a televised address late Sunday that “a frightening phase of upheaval has begun on the Reykjanes Peninsula,” where a long-dormant volcanic system has awakened.

A volcano on the peninsula erupted for the second time in less than a month on Sunday, with orange lava bursting through two fissures near the fishing village of Grindavik. Authorities had ordered residents to leave the site hours earlier as a series of small earthquakes signaled an impending eruption.

The nearby Blue Lagoon geothermal spa – one of Iceland’s biggest tourist attractions – was also closed, saying it would remain closed until at least Tuesday.

Grindavik, a town of 3,800 people about 50 kilometers (30 miles) southwest of the capital Reykjavik, was evacuated back in November when the Svartsengi volcanic system awoke after nearly 800 years with a series of earthquakes that opened large cracks in the earth between the city and Sýlingarfell, a small mountain to the north.

The volcano finally erupted on December 18, sending lava flowing away from Grindavik. Residents were allowed to return to their homes on December 22nd.

Since then, rescue workers have built defensive walls that have stopped much of the new eruption’s lava flow just short of the city.

The Icelandic Meteorological Office said on Monday that “the flow of lava has decreased since the eruption fissures that opened yesterday.” Flow from the southern eruption fissure, which emerged near the city limits around midday yesterday, appears to have stopped. “The majority of the remaining lava flow is now directed southwest along the protective barriers and its trajectory appears to have stabilized.”

No one was killed in the eruptions, but a worker is missing after reportedly falling into a fissure opened by the volcano.

“We do not yet know how this outbreak will develop, but we must still take the measures within our power,” the president said. “We will continue to fulfill our responsibilities and continue to stand together.

“We continue to hope for the best possible outcome in the face of these enormous forces of nature,” he added.

Iceland, which sits above a volcanic hotspot in the North Atlantic, experiences an eruption every four to five years on average. The most devastating recent eruption was the eruption of the Eyjafjallajökull volcano in 2010, which spewed clouds of ash into the atmosphere and paralyzed transatlantic air traffic for months.

The latest eruption is not expected to release large amounts of ash into the air. Operations at Keflavík Airport are continuing as normal, said Gudjon Helgason, spokesman for airport operator Isavia.