Bodies were still being pulled on Tuesday from the wreckage of a mosque blast that targeted police officers in northwestern Pakistan, killing more than 80 people and wounding 150 more.

The attack happened on Monday during afternoon worship in the provincial capital of Peshawar, close to areas along the Afghan border where militancy has been steadily rising.

Overnight, at least nine bodies were recovered as rescuers sifted through the rubble of the mosque's collapsed wall and roof.

"This morning we are going to remove the last part of the collapsed roof so we can recover more bodies, but we are not hopeful of reaching any survivors," Bilal Ahmad Faizi, a spokesperson for the rescue organisation 1122, said.

Muhammad Asim Khan, a spokesman for the main hospital in Peshawar, said that 83 people had been killed, with the death toll rising as more bodies arrived from the scene.

At least 20 of the slain police officers were later buried after a prayer ceremony, with coffins lined up in rows and draped in the Pakistan flag.

They were laid to rest with a guard of honour, a police official said.

Shahid Ali, a policeman who survived, said the explosion took place seconds after the imam started prayers.

"I saw black smoke rising to the sky. I ran out to save my life," the 47-year-old said.

No group has yet claimed responsibility for the attack, amid a worsening security situation in the country.

The police headquarters in Peshawar is in one of the most tightly controlled areas of the city, housing intelligence and counter-terrorism bureaus, and is next door to the regional secretariat.

Provinces around the country announced they were on high alert after the blast, with checkpoints ramped up and extra security forces deployed, while in the capital Islamabad, snipers were deployed on buildings and at city entrance points.

"Terrorists want to create fear by targeting those who perform the duty of defending Pakistan," Prime Minister Shehbaz Sharif said in a statement.

The drastic security breach came on the day United Arab Emirates President Mohamed bin Zayed Al Nahyan had been due to visit Islamabad, although the trip was cancelled at the last minute due to bad weather.

Pakistan is also preparing to host an International Monetary Fund delegation on Tuesday as it works towards unlocking a vital bailout loan to prevent a looming default. (AFP)