Eleven people were killed after a gas leak incident in the Giaspura area in this Punjab district on Sunday, police said.

Four more people, who were taken ill, are undergoing treatment at a hospital, they added.

The source of the leakage and the type of the gas are yet to be ascertained, police said, adding that the area has been sealed while a fire brigade and an ambulance have been deployed there.

A 50-member team of the National Disaster Response Force (NDRF) has also reached the site.

Police said the casualties comprise five females and six males. Two boys aged 10 and 13 are among the 11 who died in the incident, they said.

An NDRF official said it was yet to be found which gas caused the deaths. “We will check it first then we will let you know,” the official said in a response to a query.

A district administration official said a team of the NDRF, which has reached here, will ascertain the source and the type of gas.

As it was a thickly-populated area, the immediate priority was to evacuate people from the place, the official further said.

Punjab Chief Minister Bhagwant Mann said the incident was very painful and added that all possible help is being provided.

“The incident of gas leak in Giaspura area of Ludhiana is very painful. Teams of police, district administration and NDRF are present on the spot. Every possible help is being provided..,” Mann said in a tweet in Punjabi.