Nine people were wounded by a bomb explosion in northwestern Pakistan on Thursday in the latest violence against security forces in the region.
Elsewhere in the tribal belt along the border with Afghanistan, security forces traded gunfire with militants at checkpoints near the scene of recent violence, officials said.
In North West Frontier Province, a police van carrying prisoners and officers back from a court hearing was hit by a bomb blast near the town of Timergara, police officer Shahjehan Khan said.
Six prisoners and three officers were wounded, Khan said.
He said police were investigating the explosion, and refused to speculate on who may have been responsible.
In North Waziristan, security forces at checkpoints near the main town of Miran Shah opened fire on suspected militants on Thursday, officials said on condition of anonymity because they were not authorized to speak to the media. There were no reports of injuries.
Taliban militants have been expanding their influence from strongholds in the tribal belt, and Pakistan President Pervez Musharraf is under growing pressure from his key international backer, the United States, to crack down.
Since a bloody army siege of Islamabad's radical Red Mosque earlier this month, Pakistan has sent thousands of troops to the northwest, triggering a fierce militant response. More than 300 people who have died in violence across the country this month.
Militants have killed dozens of soldiers with suicide attacks in North Waziristan.
In North West Frontier Province, two suicide bombers and a roadside bomb simultaneously struck a military convoy earlier this month, killing 11 soldiers and three civilians.
Small-scale roadside bombs have also hit police in recent days, without causing serious casualties.