Pakistani paramilitary forces rushing to protect government buildings and bridges in a Taliban-infiltrated district just 60 miles from the capital were met with gunfire Thursday that killed one police officer, authorities said.

It was not immediately clear if the gunmen were Taliban militants, but the clash in Buner district is likely to heighten concern about the viability of a government-backed peace deal with the Taliban in northwest Pakistan.

The deal imposes Islamic law in a large segment of the country's northwest in exchange for peace with Taliban militants in the neighboring Swat Valley.

In recent days, the valley's militants have entered Buner in large numbers — establishing checkpoints, patrolling roads and spreading fear. Their movement has bolstered critics' claims that the deal would merely embolden the militants to spread their reign to other parts of the province bordering Afghanistan.

The U.S. has become one of the deal's foremost critics.

"I think the Pakistani government is basically abdicating to the Taliban and the extremists," U.S. Secretary of State Hillary Clinton told lawmakers in a hearing Wednesday in Washington. But on Thursday she added that she thought Islamabad was beginning to recognize the severity of the threat posed by militants.

Also Thursday, U.S. special envoy Richard Holbrooke called Pakistani President Asif Ali Zardari to discuss the situation in the region, Zardari's office said without specifying if Buner was mentioned. The call came as the chairman of the U.S. joint chiefs of staff, Adm. Mike Mullen, was in Pakistan for talks with officials.

Six Frontier Constabulary platoons arrived Wednesday in Buner, a district with more than a half-million residents, said Syed Mohammed Javed, a government official who oversees the area covered by the peace deal. He would not say if the deployment was in direct response to the Taliban presence.

Javed did not specify the number of troops involved, but a platoon typically has 30 to 50 members.

On Thursday, gunmen opened fire on a security convoy that included some of the Frontier Constabulary. The gunfire killed an escorting police officer and wounded another in the Totalai area, said Hukam Khan, an area police official.

He refused to speculate on the identities of the gunmen.

Maj. Gen. Athar Abbas, the Pakistan Army's chief spokesman, insisted the situation in Buner was not as dire as some have portrayed — saying militants were in control of less than 25 percent of the district, mostly its north.

"We are fully aware of the situation," Abbas said. "The other side has been informed to move these people out of this area."

However, a meeting between tribal elders and the Taliban on Thursday in Daggar, Buner's main town, ended without any indication that the Taliban would withdraw.

In an indication of the fear spread by their advance, Daggar's bazaar as well as the road into the district were almost deserted, according to an AP Television News reporter who visited the area and witnessed part of the meeting.

Police and government officials in Buner appear to have either fled or are keeping a low profile, and there was no sign of the Frontier Constabulary forces in the town.

Two Taliban representatives declined to comment after the meeting, driving away in a pickup truck full of gun-toting associates. However, a Taliban leader who goes by the name Commander Khalil said the militants had agreed to stop patrolling in Buner, though they would still keep armed guards in their vehicles.

"We are here peacefully preaching for Sharia. We don't want to fight," Khalil told an AP reporter by phone.

Another Taliban leader, Maulana Muhammad Bashir, said the militants had agreed not to target those who had opposed them in the past in Buner — a key demand of local leaders, some of whom had raised tribal militias to fight the Taliban.

Javed Khan, a top administrator in Buner, said the Taliban agreed to not exhibit weapons or interfere with government offices. The militants also promised to leave aid groups alone, and return seized government vehicles, he said.

Nasir Laik, an elder at the Daggar meeting, said the militants could stay so long as they only preached.

According to officials, the Taliban have established a base in the village of Sultanwas and set up positions in the nearby hills. Residents say they have been broadcasting sermons by radio about Islam and warning barbers to stop shaving men's beards.

President Asif Ali Zardari signed off on the peace pact last week in hopes of calming Swat, where some two years of clashes between the Taliban and security forces have killed hundreds and displaced up to a third of the one-time tourist haven's 1.5 million residents.

The cease-fire agreement with militants covers Swat and other districts in the Malakand Division, an area of about 10,000 square miles near the Afghan border and the tribal areas where al-Qaida and the Taliban have strongholds.

Supporters say the deal takes away the militants' main rallying call for Islamic law and will let the government gradually reassert control — a theory yet to be seriously tested.

Also Thursday, dozens of militants armed with guns and gasoline bombs attacked a truck terminal near Peshawar, also in northwest Pakistan, burning five tanker trucks carrying fuel to NATO troops in Afghanistan, said Abdul Khan, a local police official.

Security guards fled, and the assailants escaped before police arrived, Khan said.

NATO and the U.S. military insist that their losses on the transport route remain minimal and have had no impact on their expanding operations in Afghanistan. However, they have been seeking alternative routes through Central Asia.

Meanwhile, the Pakistani army killed at least 11 militants on the third day of an operation against insurgents in the northwest's Orakzai tribal region, a military statement said. The army has used airstrikes to take out militants hideouts in different pockets of the tribal region, and had already killed 27 militants in the past two days.