Lava flowing down one side of Sicily's Mount Etna caused a powerful blast that injured 32 people, none seriously, local authorities said yesterday.

The late-night explosion devastated a building that forms part of the Sapienza tourist complex perched high on the flanks of Europe's most active volcano, raining incandescent debris on firefighters and onlookers.

Etna has been spewing ash and lava since it was jolted into life by a series of earthquakes in October. It has claimed no lives but has destroyed several buildings and kept the airport at nearby Catania, Sicily's second city, closed for days on end.

A tongue of lava reached the tourist building late on Monday and firefighters were on the site when the blast ripped through it two hours later, local authorities said.

Three were taken to hospital with burns and cuts but their injuries were not considered life-threatening.

The cause of the explosion, heard in the village of Nicolosi 15 kilometres away, remained unclear some 12 hours later. Rescue workers said the lava may have caused overheating in a water cistern, or in the oil reservoir of a power generator.

A thick river of lava has threatened the Sapienza complex for several weeks and was inching its way towards a souvenir shop there later yesterday.

Prime Minister Silvio Berlusconi said the government would consider giving emergency funding to the Catania region to help it overcome the economic damage wrought by Etna's eruption.