Thirty people have died in the garment factory collapse in Bangladesh, official sources said on Tuesday.

Over 100 workers are still feared trapped inside the factory, which is situated in Gazipur district, 32 km northwest of Dhaka, and which caved in on Monday after a boiler exploded

Search for survivors continued overnight without much success due to lack of proper equipment in the factory, the sources said.

The over 1,000 rescue workers -- firefighters and police officials -- pressed into service under the army's supervision were forced to sift through the rubble using bare hands and crowbars, they added.

Hundred injured workers have been rescued and rushed to nearby hospitals, they said.

Over 200 night-shift workers were in the factory when it collapsed, police and survivors said.

Media reports said flouting of factory laws was the main reason for such a deadly accident.

The government has launched a probe into the incident.