Photo from AFP

A major rescue operation is under way to save dozens of people thought to be trapped in rubble after a factory collapsed in Lahore, Pakistan, the BBC reports.

At least 17 people died when the factory, which was under construction, collapsed on Wednesday.

Cranes and bulldozers are being used and the army is assisting in the rescue efforts.

The cause of the collapse is still unknown. Building safety levels are often below standard in Pakistan.

Two floors of the factory, in the Sundar Industrial Estate on the outskirts of the city, were operational, while a third was being built.