Several militants holding grenades attacked a mosque in northwest Pakistan on Friday, killing at least 18 worshippers and wounding 63 others.

Several militants holding grenades attacked a mosque in northwest Pakistan on Friday, killing at least 18 worshippers and wounding 63 others, police sources said.

"Several gunmen threw grenades before storming the Imamia mosque in Peshawar, the main city in Pakistan's restive northwest, around the time of the main Friday prayers," senior police official Rana Umer Hayat told AFP.

The attack comes two weeks after a suicide bombing at a Shiite mosque in southern Pakistan killed 61 people, the deadliest sectarian incident to hit the country in nearly two years.

Witnesses reported that a huge explosion went off, and TV footage showed people running away from the scene, some carrying injured on their shoulders, others limping, as police fired shots and checked people at a barrier.

Pakistan suffered a rising tide of sectarian violence in recent years, most of it perpetrated by extremist armed groups.