Iceland has kept the risk level for an eruption of its Bardarbunga volcano at orange, the second-highest level of significance.
Local earthquakes have caused a nearby glacier to crack, causing red-hot lava to spout through.
Huge clouds of smoke – mostly vapour and gas, rather than ash, which is dangerous for planes – could be seen coming out of the volcano.
Four years ago it was a different volcano that erupted,spreading an ash cloud and shutting down much of Europe’s airspace for around a week.
The risk of an ash cloud this time round would depend on three main factors: how high any ash would be thrown, how much ash there would be, and how fine-grained it would be.