According to authorities, a wall at a salt packaging factory in India’s western state of Gujarat collapsed on Wednesday, killing at least 12 workers.

It was unclear what caused the 3.6-metre high wall to come down but police said they will be investigating the owner of the site for negligence.

“12 people including five women and seven men have died in the incident. One person injured in the accident is under treatment,” police superintendent Rahul Tripathi told AFP.

Prime Minister Narendra Modi, who is from Gujarat, called the incident at the Sagar Salt factory in the industrial area of Havald town a “heart-rending” tragedy.

“In this hour of grief, my thoughts are with the bereaved families. May the injured recover soon. Local authorities are providing all possible assistance to the affected,” he said on Twitter.

Modi also announced 200,000 rupees ($2,578) compensation for the families of those who lost their lives.

Factory accidents are common across India, with owners ignoring basic safety requirements and often operating without permits.

A fire at a commercial building in New Delhi that manufactures Wi-Fi routers killed 27 people last week.