A blast apparently aimed at Pakistani security forces ripped through a busy market in the north-western Swat Valley today, killing at least eight people and wounding dozens of others, officials and witnesses said.
The attack in the district capital of Mingora was the latest violence in the region along the border with Afghanistan where the Pakistani military has been waging offensives against Taliban militants, who have been fighting back, often with homemade bombs.
Swat police chief Muhammad Idrees said items found at the scene of the attack suggested it may have been a suicide bombing, though an investigation would be needed to confirm it.
Witness Rahim Gul said the blast occurred as two vehicles carrying Pakistani security forces passed through the Nishat intersection, which is surrounded by small shops and stalls. But the security forces' vehicles appeared to be undamaged, Gul said.
Television footage of the scene showed a string of cars in the road that were gutted or had blown-out windows. A fire truck arrived to extinguish fires ignited by the blast and heavily armed security forces guarded the area.
Another witness, Shiraz Khan, said people could be heard crying for help immediately after the blast.
Dr Lal Noor, head of the Saidu Sharif hospital in Mingora, said at least eight people had died and 35 were wounded.
The Pakistani military launched an offensive in the mountainous Swat Valley early last year after peace deals with local Taliban collapsed and the militants took control of parts of the region just four hours' drive from Islamabad. The military took back the Swat Valley by mid-2009, but sporadic violence has continued.
The Swat Valley offensive drew strong praise from Washington, which has long urged Pakistan to do more to combat militants in the lawless tribal belt along the Afghan border and to root out al-Qaida militants believed to be sheltering there.
Pakistan followed up the Swat campaign with an offensive in the nearby South Waziristan tribal zone.
In recent months, the Taliban has been weakened by CIA missile strikes from unmanned drone aircraft in the border region that have killed some senior leaders.
This month, Pakistan also arrested three senior Afghan Taliban leaders – including the group's no2 commander – and rounded up dozens of other militant suspects, in raids sometimes carried out with US intelligence or other assistance.
Analysts are divided about whether the crackdown signals a shift in Pakistani policy in which security forces are finally going after militants who are thought to have long enjoyed sanctuary in the country, or if the arrests are part of a Pakistani strategy to position the country as a main player in any peace talks between the Taliban and the US-backed Afghan government.
In another part of the north-west, the decapitated bodies of two Sikhs were found almost a month after they were kidnapped in the Khyber tribal region, officials said today.
Local government official Jawed Khan said the family of one of the two men told authorities that kidnappers had demanded 15m rupees (£210,000) in ransom for his return.
Sikhs are a tiny minority in Islamic Pakistan, though there is a sizeable community in the north-west that has increasingly suffered persecution as Islamic extremists have gained influence in recent years.