At least 14 Pakistani schoolchildren were killed and 20 others injured when the roof of a private tuition centre operating from an under-construction building collapsed in Lahore on Tuesday, police said.

More than 30 children, aged between seven and 13 years, were attending classes at the academy, located in the densely populated Kahna Nau area, when the roof caved in, trapping them under the debris.

"So far, 14 bodies of children have been recovered from the debris," Lahore Deputy Inspector General (DIG) Operations Faisal Kamran told reporters.

Twenty injured children and a female teacher were shifted to the hospital, police said, adding that the deceased include seven girls and as many boys.

"A part of the building was under construction and labourers were busy at work when the roof collapsed. We have arrested the contractor," Kamran said.

Later, the Lahore Police in a statement said the house owner has also been taken into custody as part of the initial investigation.

Punjab Health Minister Khawaja Imran Nazir said rescue teams have completed the operation.

Lahore District Education Authority Chief Executive Officer Tariq Mahmood said the building housed a private tuition centre being run by a woman resident of the locality.

A statement by the Edhi Foundation, which also took part in the rescue operation, said the roof of the academy in the residential building in Basti Eid Gah locality "collapsed suddenly".

"The bodies of the deceased were shifted to the morgue at General Hospital," the NGO said, adding that the injured have been shifted to the hospital, where their condition was stated to be stable.

President Asif Ali Zardari expressed grief and sorrow over the tragic incident, his office said in a social media post.

"The loss of the precious lives of innocent children is extremely heartbreaking for the entire nation; effective safety measures are indispensable to prevent such tragedies," it said.

Prime Minister Shehbaz Sharif, in a statement, prayed for the deceased and extended his condolences to the bereaved families. He also wished the injured a speedy recovery and directed that they be provided with “every possible medical aid”.

Punjab Chief Minister Maryam Nawaz directed police and district authorities to identify those responsible for the collapse and initiate criminal proceedings against them.

"As a mother, I can understand the pain of the parents. I have no words to express the depth of this tragedy," she said in a statement.

The provincial health authorities declared an emergency at Lahore General Hospital and directed senior administrative officials, doctors, nurses and paramedical staff to ensure immediate treatment of the injured.

According to a Geo News report, roof and building collapses are common across Pakistan, mainly because of poor safety standards and shoddy construction materials.

Last year in July, 27 people were killed and 10 others injured when a five-storey building collapsed in the impoverished area of Karachi's Lyari.

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