Pakistani troops backed by helicopter gunships and fighter jets killed 24 militants Monday, an official said, in an operation praised by U.S. commanders worried about Taliban sanctuaries near the Afghan border.

The Pakistani operation comes amid tension with the U.S. over whether the Muslim nation is doing enough to combat insurgents in its wild border region — named as a possible hide-out of Al Qaeda leader Usama bin Laden — and whether the U.S. should pursue unilateral strikes there.

On Monday, residents and intelligence officials claimed Pakistani troops fired warning shots after suspected American helicopters landed near their positions in another militant stronghold further south. The U.S. military in Afghanistan denied involvement.

Monday's deaths were the latest toll from a bloody six-week military offensive that has reportedly killed hundreds in the Bajur tribal region. Some 32 people, including three women, died Sunday, senior government official Iqbal Khattak said.

U.S. officials say the Taliban and other militant groups use Bajur as a base from which to support the insurgency in Afghanistan.

In Bajur, Pakistani forces used helicopter gunships, fighter jets and heavy artillery to attack suspected militant positions in various areas, Khattak said. As well as 24 militants killed, another 22 were wounded, he said.

In a statement late Sunday, the military said ground forces secured several areas and were advancing toward Loi Sam, a key region for the militants. Khattak said troops were also trying to secure Nawagai, a strategic town on a main road.

Casualty figures and details of the operation were difficult to confirm independently because of the region's remote and dangerous nature.

The government said late last month it would cease military operations in Bajur for the Muslim holy month of Ramadan, but reserved the right to retaliate against insurgent activities.

Army spokesman Maj. Gen. Athar Abbas said factors including persistent militant mortar attacks and threats to pro-government tribes prompted the military to restart its operation.

Abbas said the issue "has to be resolved once and for all."

"It may take a long time. We cannot just hand over this area to the Taliban," he said.

Maj. Gen. Jeffrey J. Schloesser, who commands U.S.-led troops in eastern Afghanistan, said earlier this month that he was "really encouraged" by the Pakistani operation in Bajur and that it had reduced violence across the border.

He also praised cooperation between U.S.-led and Pakistani forces ranged along the mountainous, ill-mapped frontier.

However, a series of suspected U.S. missile strikes and an American-led ground assault in Pakistani territory in the northwest in recent days have prompted official protests from Pakistan's military and government.

Civilian leaders have indicated they want to resolve those differences through diplomacy. Pakistan new president, Asif Ali Zardari, is expected to discuss the incursions with British Prime Minister Gordon Brown in London this week.

However, Pakistan army chief Gen. Ashfaq Parvez Kayani has said Pakistan will defend its sovereignty "at all cost" and that there is no agreement for America to conduct raids across the frontier.

On Monday, two Pakistani intelligence officials said several helicopters landed shortly after midnight near Angoor Ada, the same area of the South Waziristan region where the recent U.S. ground raid took place.

The officials, who asked for anonymity because they are not authorized to talk to media on the record, said Pakistani troops stationed nearby fired warning shots from light weapons. The helicopters departed toward Afghanistan shortly afterward, they said, citing local informants.

The officials said the helicopters were believed to be American, but provided no evidence.

Mohammed Noor, a local resident, said he and his family heard helicopters, then gunfire.

"We are happy that our government and our army has tried to block American helicopters," Noor said by telephone. "If our government helps us, then we can defend ourselves."

Army spokesman Maj. Murad said there was firing in the area, but that the military didn't know who was responsible.

Capt. Scott Miller, a spokesman for the U.S.-led coalition in Afghanistan, said the military had checked the report with its units and found that none were involved.