QUETTA, Pakistan - A bomb exploded Friday at a religious school that police said was affiliated with a pro-Taliban political party, killing five people and wounding 10 more.

Television footage showed a gaping hole in the rough mud wall around the seminary near the southwestern city of Quetta and one partly demolished adjacent room.

Police said the blast occurred in the wrecked room but didn't indicate if it was an attack or if the bomb had been kept there. One witness claimed it was caused by a suicide bomber.

Quetta, the intrigue-filled capital of Baluchistan province, has a rich cast of violent groups.

The city is considered a hub for Taliban militants fighting in neighboring Afghanistan. It has a history of sectarian violence. The province is also the scene of a low-level insurgency waged by ethnic Baluch nationalists seeking more autonomy.

Quetta police chief Wazir Khan Nasir said investigators were still trying to work out what kind of bomb it was and were questioning students and staff at the school.

He said the school was run by Jamiat Ulema-e-Islam, a hard-line Islamist party that is part of Pakistan's ruling coalition government, and had not been registered with authorities.

However, a local party leader denied any knowledge of the seminary and suggested the incident was staged to discredit religious schools.

"We regret the death of the students who were martyred in this incident," Hafiz Hamdullah told The Associated Press. "We fear that somebody is planning a crackdown against madrassas."

At a city hospital, a man who identified himself as Shahbaz Ahmad told reporters he had seen students scuffling with a man who tried to push past them after they asked him why he wanted to enter the compound.

"When they barred his way, he blew himself up," Ahmad, a young man with a black beard, told reporters at a city hospital. Ahmad had no visible wounds, but moments later, he collapsed unconscious and doctors rushed to revive him.

Later Friday, unknown gunmen riding a motorbike opened fire on a police patrol vehicle in Quetta, killing one officer and wounding one policeman and a passer-by, police official Raja Ishtiaq said. It was unclear if the two incidents were related.

Pakistani officials have warned that militancy could heat up following a wave of cross-border strikes on militant bases by U.S. forces in Afghanistan.

On Friday, militants distributed pamphlets in a Pakistani town near the border saying that a U.S. missile strike in the South Waziristan tribal region on Wednesday had made a regional peace deal with the government "worthless."

It accused Pakistani intelligence agents of involvement in the U.S. strike and threatened unspecified action against tribesmen or aid groups cooperating with Pakistani security services.

U.S. officials claim that peace deals sought by Pakistani authorities in its tribal areas have freed up militants to mount attacks in Afghanistan.

Pakistani officials insist they are committed to their country's seven-year alliance with Washington to combat militants and terrorists. Troops are battling rebels in two regions in the northwest.

Officials and analysts say al Qaeda and Taliban militants are using hardline clerics to convince some religious students to carry out suicide attacks on both sides of the border.