A powerful explosion in the Turkish capital collapsed two stories of a construction machinery factory on Thursday, killing at least three people, injuring some 30 others, and leaving several people trapped under debris, an official said. Fethi Yasar, mayor for the area, said a few people were believed to be trapped, and a search and rescue teams has arrived at the scene in an industrial area of the city to help them out. Mr. Yasar said around half the 80 workers of the factory escaped unharmed. The explosion ripped off the buildings glasscovered facade and shattered neighbouring buildings windows. Twisted metals and concrete slabs were strewn around the area.