U.S.-led forces in Afghanistan fired across the border into Pakistan in a strike against Taliban militants, but the Pakistani army said Thursday that two women and two children were killed.

Anger at civilian deaths and concern that they fuel extremism could persuade the incoming Pakistani government to ease off a U.S.-backed policy of using military force to root out militants.

But the attack also illustrates Washington's concern at how the Taliban and Al Qaeda continue to use Pakistan's lawless border area as a base for attacks in Afghanistan.

[A Defense official confirmed to FOX News Thursday that at around 11 p.m. local time yesterday U.S. forces in the southeastern region of Afghanistan launched an attack on a Taliban leader believed to be just miles away from the border in Pakistan.]

[This official said the U.S. military has not yet been able to determine the success of the strike. The strike came in the form of artillery rounds and was based on information coming from U.S. intelligence sources. Strikes of this nature are "normally done in cooperation with the Pakistanis."]

A homicide bomber rammed a convoy of U.S. troops in the Afghan capital on Thursday, killing six civilians, while the American-led coalition said it killed a dozen militants in the southern province of Helmand.

In Tangrai, a Pakistani village of about 40 houses surrounded by fields and mountains, villagers led an Associated Press reporter to the rubble of the house hit in the cross-border attack Wednesday morning. Only one of its four walls was still standing among a tangle of mud bricks, bedding and cooking pots.

"We are innocent, we have nothing to do with such things," said Noor Khan, a black-bearded greengrocer who said the house was his family home. He said a total of six civilians died — four women and two boys — all of them his relatives. "We are poor people just trying to earn a living."

In Afghanistan, a spokesman for the American-led coalition said troops using "precision-guided munitions" hit a compound about 1.5 kilometers (1 mile) inside Pakistan.

Maj. Chris Belcher said the troops were responding to an "imminent threat" and that the coalition informed Pakistani authorities after the strike.

"We received reliable intelligence indicating senior Haqqani Network members were in the compound at the time of the strike," Belcher said Thursday in Kabul.

Siraj Haqqani is a prominent Afghan militant. On Wednesday, a coalition statement accused Haqqani of organizing a homicide attack that killed two NATO soldiers at an Afghan government office on March 3. It said Haqqani "has become the most dangerous Taliban leader in Afghanistan."

It was not immediately clear whether the coalition forces fired from the ground or the air or what weapons were used. Belcher said he could not comment on what the threat was and had no information on casualties.

Pakistan's army, which has received billions of dollars from Washington to fight Al Qaeda and the Taliban on its side of the border, initially said the incident was an accident.

Spokesman Maj. Gen. Athar Abbas said five artillery shells fired by coalition forces strayed into Pakistan's North Waziristan region. One shell hit a home in the village, killing two women and two children, he said.

Asked later about the coalition saying it had hit the compound deliberately, Abbas said the government had summoned a coalition representative to appear on Friday.

"We have called for an explanation of whatever statement they have given," Abbas said. Firing across the border "is a violation and second, civilians were killed," he said.

Asked whether militants were also present, Abbas said only that: "We have asked them to explain how the civilian casualties occurred."

Pakistan has deployed some 90,000 troops to hunt down militants in its border regions. President Pervez Musharraf has sought to convince Pakistanis that they are fighting to protect their own country, not just for America's sake.

But with violence escalating in both Afghanistan and Pakistan, many here hope the anti-Musharraf parties that triumphed in parliamentary elections last month will scale back military activities and seek dialogue with militant groups, whose influence has been growing.

Ahsan Iqbal, a spokesman for the party of former Prime Minister Nawaz Sharif, said the new parliament would review its counterterrorism strategy.

"Pakistan's integrity and territorial sovereignty should be respected," Iqbal told AP. "Killing of innocent people is highly deplorable and there should not be any repeat."

There have been several incidents in the past of coalition fire from Afghanistan landing in Pakistani territory.

Some incidents may be due to the poor demarcation of the long, rugged border. In June last year, a rocket fired during a battle between U.S.-led NATO forces and insurgents in Afghanistan struck a home in North Waziristan, killing 10 civilians.

But there have also been several cases in which unmanned U.S. drones have fired missiles at suspected militant hide-outs in Pakistan's border regions, including a strike in January that killed a senior Al Qaeda commander.

A remark last year by Barack Obama, one of the two Democrats hoping to become the next U.S. president, that he might authorize U.S. troops to strike unilaterally in Pakistan if they located Osama bin Laden triggered a storm of indignation in Pakistan.

But U.S. military officials and soldiers have said on several occasions that they already have authority to pursue or fire on militants a short distance inside Pakistan.

Pakistani officials usually deny such incidents or voice complaints that have no visible consequences, leading many to believe that cross-border strikes are carried out with Islamabad's tacit blessing.