ISLAMABAD - Pakistani troops backed by attack helicopters stepped up an operation to push the Taliban farther away from the capital Friday, saying they killed at least 55 fighters. But the government was resisting Western pressure to expand the crackdown and abandon peace talks with militants who want to impose their brand of Islam across this nuclear-armed country.

The army launched the drive to retake Buner, a poor, hilly region just 60 miles from Islamabad, on Tuesday after Taliban from the neighboring Swat Valley overran it under cover of a controversial peace pact.

The Obama administration has welcomed the assault. It views the Swat deal, which calls for the imposition of Islamic law in the surrounding area of northwest Pakistan bordering Afghanistan, as a surrender to allies of al-Qaida. And it has expressed growing doubts about Pakistan's stability as the Taliban have edged closer to Islamabad.

Washington is particularly concerned because it considers stability in Pakistan -- and rooting out its militant sanctuaries -- critical to success in the Afghan war.

But the government in Islamabad is refusing to extend the operation beyond Buner and halt the peace talks favored by many Pakistanis skeptical of Western goals in the region. The army expects to wind up the Buner operation within a week of when it started.

The country has launched several offensives against Taliban militants in the border region in recent years. The raids have killed scores of extremists but alienated many Pakistanis.

But there has been little criticism of the current operation so far, most likely because the militants advanced after signing a peace agreement with the government.

On Friday, the army said its troops routed about 80 militants dug in on the Ambela Pass leading into Buner from the south and were trying to link up with government forces holding the main town of Daggar.

Soldiers and helicopters in the Ambela area destroyed about a dozen cars and motorbikes laden with explosives, apparently for suicide missions, spokesman Maj. Gen. Athar Abbas said.

Two soldiers died and eight more were wounded when a suicide bomber detonated explosives hidden in a house beside a road, Abbas said at a news conference.

He said warplanes bombed several militant bases farther north and that at least 55 militants had died in the previous 24 hours, bringing the total killed since operations began to more than 100, according to the army.

Security forces have barred most reporters from entering the area and phone lines were down, making it hard to verify the army's account of the fighting.

Abbas also accused militants of violating the terms of a cease-fire in Swat Valley by re-establishing roadblocks, planting roadside bombs and kidnapping policemen.

An army statement in Swat said Pakistani troops repulsed an attack on a security forces checkpoint in Khwazakhela in the valley Friday.

The spokesman for the Swat Taliban could not be reached for comment.

Swat's Taliban appear to have been emboldened after their bloody, two-year campaign in the valley led the government in February to agree to a peace accord that imposes Islamic law in the surrounding Malakand division, a wide swath which includes Swat and Buner.

Critics warn that militants, who have beheaded opponents and burned down girls schools, will manipulate the new Islamic courts to impose a draconian version of Islamic law and create a haven from which they are sure to expand.

But Pakistani leaders say setting up Islamic courts -- a popular demand in Swat -- will rob the militants of their main rallying call and make it easier to justify a crackdown on those who refuse to renounce violence.

Sufi Muhammad, a hardline cleric mediating the peace process, suspended his work earlier this week to protest the army operation. But he held talks with a provincial government leader Friday in the northwestern town of Timergara.

Provincial Information Minister Iftikhar Hussain said an agreement was close on the main sticking point -- which senior Islamic judges should be appointed to the new courts in Malakand.

"We believe that we should seek solutions from both sides for the sake of peace," Hussain said. "I think we are close to breaking the deadlock."

Muhammad said the Taliban would stop fighting if their version of Islam carries the day.

"If the government enforces (Islamic law) in its true letter and spirit, I guarantee that the Taliban will lay down their arms and help restore peace in this region," Muhammad told reporters after the meeting.