Police investigators confirm last week's powerful blast in Czech capital caused by gas leak

PRAGUE – Investigators have confirmed that the blast last week that ripped open a central Prague office building and injured some 40 people was caused by a gas leak.

Police spokesman Jan Danek says the gas leaked from an underground pipeline located several meters (yards) from the damaged building.

Danek didn't given further details Thursday. He says the investigation has not been concluded but authorities believe it was an accident.

The April 29 explosion badly damaged the building, which belongs to the Air Navigation Services of the Czech Republic. It shattered windows in the surrounding area, including the National Theater.

Six foreigners were among the injured.

Authorities had ruled out a terrorist attack.