Eight hundred people have been evacuated in Iceland because of a flood from a glacier that melted after the country's second volcano eruption in less than a month, police said.
Iceland's Department of Civil Protection said the immediate area around the eruption in the southeast of the country was at risk of flash floods.
The volcano sent up the huge cloud of ash that has brought air chaos to much of northern Europe.
Police spokesman Vithir Reynisson said 800 people had been moved, many for a second time in less than 24 hours. Hundreds had to flee the floods after the eruption started on Wednesday.
The civil protection department said there was an "imminent and immediate danger of flash floods. Reports confirm a large body of water emerging from under" the glacier.
"The water is expected to breach the flood barriers," the department added.
"We think that houses and roads and bridges are in danger of destruction," police spokesman Reynisson added.
He said the evacuation started shortly before 1900 GMT after glacier waters started flooding the Markarfljot river.
University of Iceland volcanologist Armann Hoeskuldsson told AFP yesterday the eruption occurred within the glacier ice, melting it and triggering floods.
"The situation is critical," he said.
The eruption came under the Eyjafjallajokull glacier in the south of the country at around 0100 GMT on Wednesday, forcing the evacuation of between 700 and 800 people for a first time.