Authorities on Saturday were investigating a suicide attack that killed 95 people and injured dozens more at a volleyball match in Pakistan's North-West Frontier Province, police said, DPA reported.
"We have found some clues that can lead to the perpetrators of the action, and some arrests are expected by the evening," district police chief Mohammad Ayub Khan said by phone.
Friday's bombing in the Shah Hassan Khel village was the latest and deadliest in a series of militant strikes against civilian and government targets in the country since mid-October.
"The terrorists arrived in two vehicles," Khan said. "One blue colour vehicle immediately entered the grounds and exploded there. The second vehicle that was parked at some distance drove back and headed towards Lakki Marwat."
The explosion demolished around 30 nearby houses and a market, killing six children and two women inside. Five paramilitary soldiers were also among the dead.
Khan said 250 to 300 explosives were used in the bombing, which left a crater 1-2 metres deep in the playing ground.
US Secretary of State Hillary Rodham Clinton late Friday condemned the bombing, saying her country would continue to provide support to Pakistan as it confronts terrorism within its borders.
"The United States strongly condemns today's terrorist attack on civilians in Pakistan, and we offer our condolences to the families of the victims and all the people of Pakistan," Clinton said.
No one had claimed responsibility for the attack, but residents said militants might have been seeking revenge for civilian efforts to drive out the Taliban from the village.
Pakistani troops backed by helicopter gunships and artillery carried out an offensive against Islamist insurgents in Shah Hassan Khel about three months ago, killing dozens of Taliban militants and forcing the rest to flee to the adjoining North Waziristan tribal district.
After the operation, local residents formed a peace committee and raised a tribal militia to prevent Taliban forces from returning, a development that infuriated the rebels.
Mushtaq Marwat, a member of the peace committee, said the residents began receiving threats from militants days before the bombing.
Another member of the committee, which was holding a meeting in a nearby mosque when the blast occurred, said the "smoke engulfed the whole village after the attack."
"The broken pieces of doors and windows fell on us, but all the members of the peace committee remained unhurt," the unnamed committee member told the Pakistani daily The Nation.
Pakistan's north-western region, especially the tribal areas along the Afghan border, have become safe havens for insurgents since 2001 when US-led forces ousted the Taliban's regime in Afghanistan.
Tens of thousands of Pakistani troops are currently engaged in a major operation against the Islamist extremists in the South Waziristan tribal region. The 10-week assault has left more than 600 Taliban fighters dead, according to the army.
The militants have responded with a campaign of retaliatory suicide bombing against civilian and government installations, killing more than 600 people since mid-October.