A suicide bomber blew up a car packed with explosives in a crowd of people watching a volleyball game in a northwest Pakistan village on Friday, killing 40 spectators, police said.
More than 50 people were also injured in the blast in Bannu district in North West Frontier Province, which is plagued by attacks by Taliban rebels avenging military offensives aimed at crushing their northwestern strongholds.
"The villagers were watching the match between the two village teams when the bomber rashly drove his double-cabin pick-up vehicle into them and blew it up," district police chief Mohammad Ayub Khan told AFP.
"At least 40 people have died and the toll is likely to rise."
Another local police chief Habibullah Khan said 50 people were wounded in Shah Hasan Khan village, 30 kilometres (18 miles) south of Lakki Marwat town and near the tribal district and Taliban stronghold South Waziristan.
Mushtaq Marwat, a member of a local anti-Taliban group, told the private Geo television station that the so-called "peace committee" was meeting at a nearby mosque when the bomber stuck the village field outside.
"Suddenly there was a huge blast. We went out and saw bodies and injured people everywhere... ten houses and three shops were destroyed," he said, estimating that the death toll was going to rise significantly.
Mohammad Ayub Khan said that women and children were pulled from the rubble of a nearby house that collapsed in the blast, and said that the remote area was struggling to cope with the scale of the attack.
"It is a remote and backward area and the local hospital does not have a doctor. Local residents have put the casualties into their own vehicles and drove to Lakki Marwat hospital," he added.
The police and army launched an operation against Taliban militants in Bannu last year. They claimed success but unrest has rumbled on, and Mohammad Ayub Khan said he thought the Islamist extremists were behind the attack.
"Now they have found an opportunity to carry out this attack," he said.
Prime Minister Yousuf Raza Gilani condemned the bombing, and said "such terrorist acts cannot weaken the government's resolve to fight the menace of terrorism till its complete elimination," according to a statement from his office.
The military have launched their most ambitious offensive yet against homegrown Taliban militants in South Waziristan tribal district. They sent about 30,000 troops into the region on October 17.
Security has plummeted over the last two and a half years in Pakistan, where militant attacks have killed more than 2,800 people since July 2007 and which Washington has established as a front line in its war on Al-Qaeda.
Insurgents have responded to the 2009 offensives with a wave of attacks, increasingly targeting civilians and causing massive casualties.
On Monday, 43 people were killed in a suicide bombing at a Shiite religious parade in Pakistan's southern financial hub Karachi.