Pakistan stands with the U.S. against international terrorism, the Muslim nation's presidential front-runner wrote in a column appearing Thursday amid furor over a U.S.-led cross-border attack in Pakistani territory.

The raid in the South Waziristan tribal region was the first known foreign ground assault in Pakistan against a Taliban haven. The Pakistani government summoned the U.S. ambassador to protest the incursion, which officials said killed at least 15 people, including civilians.

An American official, speaking on condition of anonymity because of the sensitivity of cross-border operations, confirmed to The Associated Press that U.S. troops conducted the raid Wednesday about 1 mile beyond the Afghan frontier.

The boldness of the thrust fed speculation about the intended target. But it was unclear whether any extremist leader was killed or captured in the operation, which occurred in one of the militant strongholds dotting a frontier region considered a likely hiding place for Usama bin Laden and Al Qaeda's No. 2 leader, Ayman al-Zawahri.

Foreign Minister Shah Mahmood Qureshi condemned the attack in an impassioned speech to lawmakers Thursday, saying it "violated the sovereignty of Pakistan." He also said "no important terrorist or high-value target" was killed.

"Innocent citizens, including women and children, have been targeted," Qureshi said. The ministry's spokesman said officials had no indication U.S. forces captured anyone in the raid.

Foreign Ministry spokesman Mohammed Sadiq said Thursday the government had no information Al Qaeda leaders were in the area at the time. "If so, we would have taken action," Sadiq said, adding authorities had no indication U.S. forces captured anyone in the raid.

A Pakistan army spokesman warned that the apparent escalation from suspected U.S. missile strikes on militant targets along the Afghan border would further anger Pakistanis and undercut cooperation in the war against terrorist groups.

The operation came days before Pakistan's weekend presidential election and threatened to complicate an already difficult relationship between the two countries.

For months now, U.S. commanders have pressured Pakistan to put more pressure on militant groups blamed for mounting violence in Afghanistan. That has stirred speculation that U.S. forces might lash out across the frontier, despite the risk of angering Pakistanis.

Suspected U.S. missile attacks killed at least two Al Qaeda commanders this year in the same region, drawing protests from Pakistan's government that its sovereignty was under attack. U.S. officials did not acknowledge any involvement in those attacks.

The main ruling Pakistan People's Party is generally considered in line with U.S. goals in the war on terror, but it has to tread carefully because of deep anti-American sentiment in the country. Many Pakistani's blame their country's partnership with the U.S. in the war on terror for fueling rising militancy in their country.

People's Party leader, Asif Ali Zardari, the widower of assassinated ex-Prime Minister Benazir Bhutto, is the leading candidate in Saturday's presidential vote by lawmakers.

In a column for The Washington Post, Zardari described global terrorism as chief among the challenges facing his country. The column mentioned an apparent assassination attempt against Pakistan's prime minister on Wednesday but did not mention the earlier cross-border raid.

"We stand with the United States, Britain, Spain and others who have been attacked," wrote Zardari, whose wife was killed in a gun and suicide blast in December. "Fundamentally, however, the war we our fighting is our war. This battle is for Pakistan's soul."

A lawmaker from the chief opposition party, that of ex-Prime Minister Nawaz Sharif, on Thursday blasted the U.S. for the attack.

"The American war against terrorism has become a war against Pakistan, and the killing of people by them at Angoor Ada is a clear example of it," Zafar Ali Shah said.

Shah said the Pakistani government should tell America that "enough is enough, and we will not help you if you kill our people."

Some administration officials have been pressing President Bush to direct U.S. troops in Afghanistan to be more aggressive in pursuing militants into Pakistan on foot as part of a proposed radical shift in regional counterterrorism strategy, the AP learned. The debate was the subject of a late July meeting at the White House of some of Bush's top national security advisers.

Circumstances surrounding Wednesday's raid weren't clear, but U.S. rules of engagement allow American troops to pursue militants across the border into Pakistan when they are attacked.

However, Pakistan army spokesman Maj. Gen. Athar Abbas said hot pursuit wasn't an issue, adding that the attack "was completely unprovoked." He said Pakistani troops were near the village and saw and heard nothing to suggest the U.S. forces were pursuing insurgents.

The raid comes at a particularly sensitive time for the Pakistan government which is trying to overcome political divisions and choose a new president on the one hand, while the army is battling the militants on the other.

Abbas said the attack was the first incursion onto Pakistani soil by troops from the foreign forces that ousted Afghanistan's hard-line Taliban regime after the Sept. 11, 2001, attack on the U.S.

He said the attack would undermine Pakistan's efforts to isolate Islamic extremists and could threaten NATO's major supply lines, which snake from Pakistan's Indian Ocean port of Karachi through the tribal region into Afghanistan.

"We cannot afford a huge uprising at the level of tribe," Abbas told AP. "That would be completely counterproductive and doesn't help the cause of fighting terrorism in the area."

American officials say destroying militant sanctuaries in Pakistani tribal regions is key to defeating Taliban-led militants in Afghanistan whose insurgency has strengthened every year since the fundamentalist militia was ousted for harboring bin Laden.

Citing witness and intelligence reports, Abbas said troops flew in on at least one big CH-47 Chinook transport helicopter, blasted their way into several houses and gunned down men they found there. He said there was no evidence any of the dead were insurgents or that the raiders nabbed any militant leader, but he acknowledged Pakistan's military had no firsthand account.

There were differing reports on how many people were killed. The provincial governor claimed 20 civilians, including women and children, died. Army and intelligence officials, as well as residents, said 15 people were killed.