BERN, Switzerland (AP) _ An explosion at an apartment building in the Swiss capital of Bern killed three people and injured 17 Thursday, police said.

Dozens of rescuers, backed by a helicopter, searched for victims in the rubble of the five-story building.

The force of the explosion tore the front off the building, leaving the roof hanging. Witnesses said windows were also shattered in a wide area around the blast.

The cause of the explosion near the town center wasn't immediately clear. Police said they couldn't yet tell if there had been a gas leak or even if the building was on the city's gas network.

The building had a car-repair garage on the ground floor and apartments above.

``It is a terrible scene, like from a bomb going off in Beirut,'' said police spokesman Beat Gross.