Images showed a massive grey cloud billow forth from the volcano on the island of Sicily, beginning about 11:24am local time (0924 GMT), according to the National Institute of Geophysics and Volcanology (INGV).
Surveillance cameras showed “a pyroclastic flow probably produced by a collapse of material from the northern flank of the Southeast Crater”, the agency said.A pyroclastic flow occurs when volcanic rock, ash and hot gasses surge from volcanos. They are extremely dangerous.The explosive activity “had transitioned to a lava fountain”, INGV said, with the plume of ash expected to dissipate towards the southwest.A red alert issued for aviation authorities said the height of the volcanic cloud was estimated at 6.5 kilometres.The nearby Catania airport was still in operation.