The death toll from the suicide blast that ripped through a mosque on Monday afternoon in Pakistan's northwest provincial capital of Peshawar has risen to 96, according to local media outlet Dawn News.

The attack happened during afternoon worship at a crowded mosque in Pakistan's northwestern city of Peshawar. Around 300 people were praying in the mosque of the Police Lines area of the city when the blast happened, killing and wounding the people, including police officials.

A frantic rescue mission was underway overnight at the mosque, which had an entire wall and some of its roof blown out by the possible suicide attack.

"Many policemen are buried under the rubble," said Peshawar police chief Muhammad Ijaz Khan, who estimated that between 300 and 400 officers usually attended prayers.

"It's an emergency situation," said Muhammad Asim Khan, a spokesman for the main hospital in Peshawar.

The death toll continued to rise as more bodies were pulled from the debris. It currently stands at 96 killed, including at least 20 police officials, with more than 200 wounded.

The militant group Tehrik-e-Taliban Pakistan has claimed responsibility for the attack, local Geo TV reported.

"The sheer scale of the human tragedy is unimaginable," Pakistani Prime Minister Shehbaz Sharif said. "This is no less than an attack on Pakistan. The nation is overwhelmed by a deep sense of grief. I have no doubt terrorism is our foremost national security challenge."

UN Secretary-General Antonio Guterres strongly condemned the deadly attack, extending his condolences to the victims' households and wishes for a quick recovery to those injured.

(With input from agencies)