JERUSALEM (AP) _ An explosion went off in a grocery store in an Arab neighborhood of Jerusalem on Saturday, injuring at least five Palestinians, police said.

Police said the blast was caused by a concentration of gas, not a bomb. The source of the gas was not known.

The explosion caused considerable damage to the grocery, located near Damascus Gate, one of several entrances to the walled Old City.

Authorities said at least five Palestinians were injured, three seiously.