At least 12 workers were killed Wednesday when part of a chemical warehouse collapsed following a powerful blast in western India, officials said.

A fire official said the dead included five women and nine other people were injured in the incident at an industrial complex on the outskirts of Ahmedabad, a major city in western Gujarat state.

"The death toll has increased to 12 which includes five women. Nine people are injured and undergoing treatment in hospital," a fire control room duty officer told AFP.

Those hurt were undergoing treatment, he added.

Eyewitnesses told reporters that the explosion ripped apart the walls of the building, including a textile facility that operated from the complex.

Ahmadabad chief fire officer M. F. Dastur said a preliminary investigation suggested the explosion was triggered by a fire in a chemical store, and the blast left the building in a pile of rubble.

India is frequently rocked by industrial disasters that experts blame on poor planning and lax enforcement of safety rules.

Prime Minister Narendra Modi said authorities were providing all possible assistance to those affected.

"Anguished by the loss of lives due to a fire in a godown (warehouse) in Ahmedabad. Condolences to the bereaved families," he tweeted.