Officials in Pakistan said a massive ground and air offensive has killed 52 militants in the northwest Khyber Pass, where a key bridge to Afghanistan was destroyed by suspected Islamist fighters earlier this week.

News agencies quoted officials as saying the assault targeted militant hideouts and also destroyed an ammunition depot and eight vehicles.

No independent confirmation was immediately available.

On Monday, militants cut a key supply route to Afghanistan when they blew up a 30-meter iron bridge and torched several stranded supply trucks.

Pakistanis mourn in front of the bodies of suicide attack victims during their funeral in Dera Ghazi Khan, 06 Feb 2009

Elsewhere in central Pakistan Friday, scores of angry Shi'ite Muslims rioted a day after a suspected suicide bomber killed dozens of worshippers near a Shi'ite mosque in the town of Dera Ghazi Khan.

Witnesses and police said protesters set fire to at least one police outpost.

A provincial police official said eight suspects have been detained in connection with the blast on Thursday, which killed at least 33 people. More than 50 others were wounded when the bomb exploded in a crowd of Shi'ite worshippers approaching the mosque for a religious ceremony.

Residents and analysts fear the blast at the Shi'ite mosque could inflame sectarian tensions. Nobody has claimed responsibility for it, but authorities quickly blamed it on extremists.

Most Pakistanis are Sunni Muslim, while Shi'ites make up about 20 percent of the country's population.

Earlier, another suicide bomber blew up his vehicle near a police station in Mingora, the main town in Pakistan's restive Swat Valley. The local police chief said at least 11 members of security forces were wounded.