Israeli officials say they believe a gas leak caused a massive explosion that gutted an apartment building, killing four people and injuring dozens of others.

Authorities said the blast occurred early Friday in the coastal city of Netanya. They describe the explosion as an accident.

Investigators are trying to determine the exact cause of the blast. They say it could have been from a gas tank used for cooking.

Police said nearby buildings were heavily damaged, with windows blown out in buildings along a busy thoroughfare.