Three people were killed and six are still missing after a gas explosion late on Saturday caused several residential buildings in the Sicilian town of Ravanusa to collapse, Italian authorities said on Sunday.

Two apartment blocks in the town of 11,000 people were completely destroyed and several other buildings had partially collapsed in the blast.

Firemen were still searching the site for survivors.

Two people were found alive under the rubble and six people were missing, the captain of the local fire brigade, Giuseppe Merendino, said on Sunday.

A spokesman for Italy’s Civil Protection said three people had been killed. Earlier the disaster agency had said four people were killed in the blast.

A priest who was celebrating mass nearby on Saturday evening said he heard a loud roar and saw flames rising from a group of houses.

“It is a huge tragedy… Let’s pray to ask God to avoid more deaths,” said the priest, Filippo Barbera.