ROME (AFP) — A huge plume of ash, gas and rock spewed forth on Monday from Italy’s Mount Etna as authorities warned people to steer clear of Europe’s largest active volcano.

Sicily’s Mount Etna has been active recently but Monday’s eruption was the most dramatic, with experts warning that such activity could continue for weeks.

Images showed a massive gray cloud billowing from the volcano on the island of Sicily, beginning at 11:24 a.m. local time, 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 — which is extremely dangerous — occurs when volcanic rock, ash and hot gasses surge from volcanos.

The explosive activity “had transitioned to a lava fountain,” INGV said, describing jets of lava being sprayed into the air.

By early afternoon, the plume had begun to dissipate.