MADRID (AP) — Spanish police say at least two people have been killed and one person has been reported missing following an explosion at an ice factory in the northern Basque fishing port of Ondarroa.

A Basque regional police spokesman said the blast occurred Monday afternoon in the factory located in the town's port area. The officer said it was believed the factory's ammonia gas compressors blew up, but the cause of the blast wasn't yet known.

The officer said the factory made ice for fish storage in the town.

There were no immediate details on how many people were in the factory at the time.

The officer spoke on condition of anonymity because of police rules preventing him from being named.