Chandigarh:  The firecracker manufacturing unit in a densely-populated residential area in Punjab's Gurdaspur district that claimed 23 lives was running illegally and its licence to manufacture crackers was expired in 2013, Senior Superintendent of Police Upinderjit Singh Ghumman said on Thursday.

"We didn't know about the (operation of the) factory. The licence of the factory was expired in 2013," he told a news channel at the disaster spot.

"We can't say anything. We can only say after the magisterial probe," he said.

The state government in a tweet said Rural Development and Panchayats Minister Tript Rajinder Singh Bajwa is overseeing the relief and rescue operations. He visited the Civil Hospital in Batala again in the morning to inquire about the health of the victims.

A total of 23 people were killed and 18 injured in the explosions. Rescuers ended their search of survivors a day after buildings were badly damaged in explosions following a blaze at the unauthorised firecracker manufacturing unit on Wednesday.

Scattered shoes, broken glass panes and vehicles were seen all over the accident spot as security personnel and rescuers were sifting through the rubble in search of survivors.

Chief Minister Amarinder Singh and local Member of Parliament Sunny Deol will visit the spot later in the day.

"The search operation has ended," a National Disaster Response Force (NDRF) official told the media.

The dead included the firecracker manufacturing unit's owner and six of his family members.

Deputy Commissioner Vipul Ujwal said seven grievously injured were referred to the Guru Nanak Hospital in Amritsar. He admitted that the factory owner had applied for the renewal of licence to manufacture the crackers.

A number of nearby buildings, including a car workshop, were badly damaged in the explosion. An elderly woman and her grandchild, who were passing close to the disaster spot, were among the dead.

The cause of the blast, which damaged the buildings in radius up to 200 metres, is yet to be ascertained, police said. Even a few stranded vehicles were flung up in the air with the blast.

Cabinet Minister Sukhjinder Singh Randhawa, who reached the accident spot on Wednesday, announced a compensation of Rs 2 lakh to the next of kin of the dead and Rs 50,000 for the injured.

The government ordered a magisterial probe into the incident.

Locals complained the firecracker unit was running illegally for the past many years. It was manufacturing and storing crackers for the wedding anniversary celebrations of Sikhism's founder Guru Nanak Dev, popularly known as 'Babe da Viah'.

"The firecracker factory has been working in this locality for many years. We have complained against the factory seven-eight times to the local administration, but no action has been taken against it," a local resident told the media.

He said a similar blast occurred in this area in January 2017, leaving one person dead and three injured.

A large number of family members of victims raised slogans against the state government over its failure to check the operation of unauthorized factory in the residential area.

Local legislator Lakhbir Singh Lodhinangal blamed the administrative failure to check the operation of unauthorized factory.

"Still there are a large number of illegal firecrackers units working in the area," he added.