Militants exchanged gunfire with security forces as troops set up sandbagged bunkers in a volatile area of northwestern Pakistan where supporters of a pro-Taliban cleric have taken up arms against the government, police said Sunday.

The rise in militancy in northwestern Pakistan has shaken the authority of President Gen. Pervez Musharraf, a key ally in the U.S. war on terror, and the latest violence represents an escalation in tensions between his government and the rebels.

Militants have clashed with security forces in the Swat district since Friday, when the military raided the stronghold of radical cleric Maulana Fazlullah.

Prime Minister Shaukat Aziz said North West Frontier Province Chief Minister Shamsul Mulk was involved in talks with tribal elders in the troubled region to prevent further bloodshed.

"Hopefully the approach being adopted will produce better results," Aziz said Sunday in the southern city of Karachi. Police and paramilitary troops continued to be engaged in fighting with militants there, he said.

Fifteen people have been killed in the violence, including six security personnel and seven civilians beheaded by militants, officials said. A suicide blast in Mingora, Swat's main town, killed 20 people Thursday.

Fresh fighting occurred Sunday in the village of Manglore and in Kot, where militants fired on security forces from mountaintop positions, a police official said on condition of anonymity because he was unauthorized to speak with the media.

Pakistan's Geo TV reported that helicopter gunships pounded suspected militant positions in Manglore, wounding 15 people, but army spokesman Maj. Gen. Waheed Arshad had no confirmation of the report.

Over the weekend, militants captured a police post in the nearby village of Charbagh.

Security forces have driven militants from Fizagat, a village on the outskirts of Mingora, the military's public relations department said on its Web site.

Meanwhile, police and paramilitary troops set up sandbagged bunkers in Kabal, a town near Mingora dominated by supporters of Fazlullah. Kabal's bazaar was closed because of an unofficial curfew, another police official said on condition of anonymity for the same reason.

In the nearby village of Tiligram, militants blew up an unmanned police post. The explosion was near a Buddha statue, but it was not known if the relic suffered any damage, one of the police officials said.

Authorities sent 2,500 paramilitary troops to Swat to fight supporters of Fazlullah, who has launched a Taliban-style Islamization campaign in the once-peaceful and scenic district, and has called for a jihad, or holy war, against the government.

Fazlullah is the leader of the banned pro-Taliban group Tehrik Nifaz-e-Sharia Mohammedi, or Movement for the Enforcement of Islamic Law.

In Malakand, a rugged area bordering Swat, authorities dropped pamphlets from airplanes on Sunday, urging residents to help "the government in purging (Malakand) of terrorists," the state-run Associated Press of Pakistan news agency reported. The government made similar appeals in Swat a day earlier.

Separately, three rockets hit the provincial capital of Peshawar before dawn Sunday, one striking a politician's house opposite the U.S. Consulate, but no one was hurt, police said.