New Delhi, 19 April

A multi-storey residential building collapsed in northeast Delhi's Shakti Vihar area in the early hours of Saturday, leaving 11 people dead and 11 injured, officials said.

Teams of the National Disaster Response Force (NDRF), fire services, Delhi Police and other volunteers carried out rescue efforts for over 12 hours at the site of the 20-year-old four-storey structure that collapsed in the Mustafabad area of the national capital around 3am.

According to police, there were 22 people at the building, most of them families. The owner of the building, Tehseen, and six from his family were among the 11 who died in the building collapse.

A police source said construction work in "two-three shops" on the ground floor could have led to the collapse. Locals also said construction work going on at a new shop could have triggered the collapse.

They also expressed concern about the fragile state of four to five buildings.

Waste water from the sewer has been seeping into the walls of the buildings for years, and over time, the moisture has weakened the structure, causing the walls to develop cracks," said Salim Ali, another resident.

The Municipal Corporation of Delhi, in a statement, said that the structure was around 20 years old and was fully occupied.

Delhi Chief Minister Rekha Gupta ordered a probe into the incident and expressed sadness over the incident.

Residents of nearby buildings who also felt the tremors described it as an earthquake and said the floor beneath them was shaking.

"We thought something hit our house but when we looked outside, we saw that the entire building next to us had turned to rubble," said Ryan, a Shiv Vihar resident who lived next to the collapsed building.

Police said they received information about the building collapse around 3.02am at Dayalpur police station. A police team rushed to Gali No 1, Shakti Vihar, where 22 people were reported to be buried under the debris.

NDRF DIG Mohsen Shahidi told PTI, "We call this a 'pancake collapse' -- a particularly dangerous type where chances of survival are minimal. Still, we hope there are lives that can be saved and we are actively searching."

He added that debris was cleared slowly as this is a highly congested area, making the rescue efforts challenging.

The use of heavy machinery was limited due to space constraints, he said.

The deceased include Tehseen, 60, the owner of the building, his son Nazeem, 30, his wife Shahina, 28, and their three children, Anas, 6, Afreen, 2, and Afan, 2, and the owner's younger daughter-in-law Chandni, 23.

Danish, 23, and Naved, 17, who are brothers, Reshma, 38, and Ishaq, 75, also died in the incident.

Six people were discharged from the hospital after receiving treatment, which included the owner's son Chand, 25, while nine people, including Tehseen's wife, remain under treatment.