A small apartment building collapsed in Palma on the island of Mallorca Monday, killing at least seven people, authorities said.

Palma city Mayor Aina Calvo told reporters that the victims, four men and three women, belong to three families that lived in the house. She identified the fatalities only as three Colombians, two Spaniards and a German couple.

Calvo said two people were injured.

Firefighters found the bodies after searching through the rubble of the four-story building with trained dogs.

The cause of the collapse, which occurred shortly after midnight Sunday, was not known. The building was about 50 years old, town hall said.

Cadena Ser radio reported that residents had been complaining about cracks in the walls, but the town hall said it had received no formal complaint.