At least 28 people have been killed and more than 150 were injured after a suicide blast in a mosque in Peshawar's Police Lines area, Reuters reported.

The blast took place at the mosque where a large number of people had gathered for prayer, police official Sikandar Khan said. The mosque was located close to a police housing block, and there were some 260 people inside when the blast occurred, according to police, Reuters reported.

"A portion of the building had collapsed and several people are believed to be under it," the police official added.

Police chief Muhammad Ijaz Khan told AFP that the incident happened during afternoon prayers in Peshawar near Afghanistan.

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

Pakistan Prime Minister Shahbaz Sharif in a statement condemned the bombing, and ordered authorities to ensure the best possible medical treatment to the victims. He also vowed “stern action" against those who were behind the attack.

Former Prime Minister Imran Khan also condemned the bombing, calling it a “terrorist suicide attack" in a Twitter post.

“My prayers & condolences go to victims families. It is imperative we improve our intelligence gathering & properly equip our police forces to combat the growing threat of terrorism," Imran Khan tweeted.