The death toll from the blast in Peshawar has risen to ninety people, the rescue operation is still ongoing and the debris of the mosque is being removed, reports Pakistan Radio.
More than two hundred victims were taken to the hospital, about a hundred wounded are still being treated in the hospital, and the rest have been discharged.
The explosion occurred when worshipers gathered in the mosque, the BBC reported.
Part of the building was destroyed, and officials said people were trapped under the rubble.
Several victims were taken to local hospitals.
A government official said that many policemen were among the dead.
The official believes that the target of the attack was the police.
Rescue work at the site of the explosion
Prime Minister of Pakistan
Shebaz Sharif
strongly condemned the terrorist acts.
In a statement, Sharif said those behind the incident "have nothing to do with Islam."
He added: "The whole nation is united against the threat of terrorism."
The explosion occurred during afternoon prayers in the city in the northwest of the country, near the border with Afghanistan, around 1:30 p.m. local time.
The video posted on social networks shows half of the wall of the building collapsing.
The mosque is covered with bricks and debris, through which people are trying to escape from the scene of the tragedy.
A rescue operation is underway inside the mosque, "the bodies of the dead are still being taken out," said Peshawar Deputy Commissioner Shafiullah Khan.
In March last year, Peshawar was targeted by another Shiite mosque bombing that killed dozens of people.
In the capital of the country, Islamabad, the police announced an increased level of danger and reported that security has been increased at all points of entry and exit to the city.