Rescue workers in Bangladesh gave up hopes of finding any more survivors in the remains of a building that collapsed five days ago, and began using heavy machinery on Monday to dislodge the rubble and look for bodies - mostly of workers in garment factories there.

In renewed anger against conditions in garment factories - a mainstay of Bangladesh's economy - hundreds of workers poured into the streets in the Dhaka suburb of Ashulia and set fire to an ambulance on Monday, the Independent TV, a private network, reported. They also tried to set fire to a factory, it said. Authorities shut down all garment factories in Ashulia and Gazipur industrial suburbs, including one that had reportedly developed cracks and was evacuated earlier.

At least 381 people were killed when the illegally constructed, eight-story Rana Plaza collapsed in a heap on Wednesday morning along with thousands of workers in the five garment factories in the building. About 2,500 survivors have been accounted for. The building owner, Mohammed Sohel Rana, was arrested Sunday in the western border town of Benapole while he was trying to flee to India.