A deadly explosion and fire along Ecuador's largest oil pipeline has left 624 people without homes, officials said Saturday.

Investigators are trying to determine the cause of Thursday's disaster, which killed seven people and injured 80.The fire started when a landslide caused a section of the Trans Ecuador pipeline, 110 miles northwest of Quito near the city of Esmeraldas, to break and spill thousands of barrels of oil.

Witnesses told local newspapers that the explosion occurred after flames reached a store selling propane canisters, igniting a fireball that burned houses and accelerated the oil spill fire.

Officials at state oil company Petroecuador, however, said they still had not determined the cause of the explosion.