Iceland examines Bardarbunga volcano 'cauldrons'
Scientists in Iceland say they are examining several 'cauldrons' found near Bardarbunga volcano, which could potentially be a sign of an eruption.
The cauldrons, depressions in the volcano's surface, each between 10-15m (49 ft) deep and 1km (0.6 miles) wide, were seen during a flight on Wednesday.
Iceland's Met Office said they were formed "as a result of melting, possibly a sub-glacial eruption."
Bardarbunga volcano has been hit by several recent tremors.
The area experienced a magnitude 5.7 earthquake on Tuesday. Experts say these earthquakes are caused as magma flows beneath the ground, cracking the rocks as it moves.
The Met Office has kept its aviation warning level - indicating the potential threat of volcanic activity to air travel - at orange, its second-highest.
Scientists discovered the new cauldrons south of the Bardarbunga volcano during a surveillance flight over the Vatnajokull ice cap - Europe's largest - on Wednesday night, the Met Office and Civil Protection Department said.
It is not clear when they were formed, and the data is still being examined, they said.
They added that they had not observed increased tremors in the area so far.
Meanwhile, the University of Iceland tweeted: "New fractures and sinkholes seen on #Bardarbunga during surveillance flight tonight. Data currently being evaluated by our geologists & IMO [Icelandic Met Office]".
However it cautioned that the sighting was limited by poor visibility, and said more information would be available after a second surveillance flight on Thursday morning.
Bardarbunga is part of a large volcano system hidden beneath the 500m-thick (1,600ft) Vatnajokull ice cap in central Iceland.
The authorities said on Saturday that a small eruption had taken place under the Dyngjujokull glacier, but that there were no signs that gases or ash had broken through the ice.
The region, located more than 300km (190 miles) from the capital Reykjavik, has no permanent residents but sits within a national park popular with tourists.
Officials have previously warned that any eruption could result in flooding north of the glacier.
Iceland's Eyjafjallajokull volcano erupted in 2010, producing ash that disrupted air travel across Europe.