At least 28 people have been killed in an explosion at a mosque in the Pakistani city of Peshawar.

The blast happened when the mosque was packed with worshippers and more than 150 people were injured.

A section of the building was destroyed, and officials say people are buried under the rubble. Several others are being taken to local hospitals.

The cause of the explosion is unclear. Prime Minister Shebaz Sharif has strongly condemned the attack.

In a statement, Mr Sharif said those behind the incident "have nothing to do with Islam".

He added: "The entire nation is standing united against the menace of terrorism".

The blast took place during afternoon prayers in the north-western city, near the country's border with Afghanistan.

Mohammad Asim, a spokesman for the Lady Reading Hospital, said that some of those injured were in a critical condition.

"It's an emergency situation," Mr Asim added.

Local media report that police, army and bomb disposal squads are at the scene.

In the capital, Islamabad Police issued a security high-alert and said security at all entry and exit points to the city had been increased. (BBC)

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