Seven persons were killed and five seriously injured on Tuesday afternoon in a powerful blast at a private explosives factory at Kukatpally on the outskirts of Hyderabad.

Cyberabad Police Commissioner M Mahender Reddy told rediff.com: "There is an explosion at the Indian Detonators Limited factory, a private plant that manufactures explosives and detonators."

At least 13 persons were reportedly working in the affected unit when the mishap occurred around 1540 IST in a building that houses detonator fuse plant No II. The entire building, part of a sprawling complex, was razed to the ground under the impact of the blast while window panes of nearby buildings were shattered.

Two heavy-duty cranes were used to remove the rubble. Seven bodies have been recovered so far.

Forensic Science Lab officials and senior police officials rushed to the spot. A preliminary investigation indicated that a short circuit could have caused the explosion.

Chief Minister Chandrababu Naidu, Home Minister T Devender Goud, Commercial Taxes Minister K Vijayarama Rao and Director-General of Police S R Sukumara visited the site.

The chief minister said the accident was the result of inadequate safety precautions. He said the factory, located in a thickly populated area, posed a safety hazard. He ordered a judicial enquiry and announced the ex-gratia of Rs 100,000 each to the families of the deceased workers. This is apart from the compensation due from the company.