Police in New Delhi arrested two people suspected of flouting fire safety regulations on Saturday after at least 27 people died and dozens more were injured in a massive blaze at a building housing a manufacturing unit for surveillance cameras.

Rescue teams worked overnight to clear the burnt out four-story building near a railway station in the western suburbs.

More than 75 people were in the building when the fire broke out on Friday evening. Some jumped from windows to save themselves, according to eyewitnesses, and firefighters broke the glass and rescued people with ropes.

Authorities said fire started in an office on the first floor and spread rapidly. Two owners of the company were arrested as part of probe to identify suspected safety violations.

The Indian capital of 20 million people is currently suffering through a heatwave, with temperatures of up to 46 Celsius (115 Fahrenheit) recorded in some places.

Last month, the heatwave caused a huge trash dump to catch fire. It burned for days, adding to the megacity’s deadly air pollution.

Prime Minister Narendra Modi offered his condolences to loved ones of the fire victims via Twitter.

“Extremely saddened by the loss of lives due to a tragic fire in Delhi. My thoughts are with the bereaved families. I wish the injured a speedy recovery,” Modi said.

He promised 200,000 rupees ($2,580) in compensation for the victims’ next-of-kin.

“Distressed by the tragic fire accident… My condolences to the bereaved families. I wish for speedy recovery of the injured,” President Ram Nath Kovind’s office tweeted.

Delhi Chief Minister Arvind Kejriwal tweeted: “Shocked and pained to know abt this tragic incident. I am constantly in touch (with) officers. Our brave firemen are trying their best to control the fire and save lives.”