AMERICAN forces launched a raid inside Pakistan Wednesday, a senior US military official said, in the first known US ground assault in Pakistan against a suspected Taliban haven, reported a private TV channel on Thursday, quoting an American news agency.  The American official, speaking on condition of anonymity because of the sensitivity of cross-border operations, said that the raid occurred on Pakistani soil about one mile from the Afghan border. The official didn't provide any other details. Pakistan's Foreign Ministry protested saying US-led troops flew in from Afghanistan for the attack on a village in the country's wild tribal belt. A Pakistan army spokesman warned that the apparent escalation from recent foreign missile strikes on militant targets along the Afghan border would further anger Pakistanis and undercut cooperation in the war against terrorist groups. 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 Osama bin Laden and al-Qaeda's No 2 leader, Ayman al-Zawahri. US military and civilian officials declined to respond directly to Pakistan's complaints. But one official, a South Asia expert who agreed to discuss the situation only if not quoted by name, suggested the target of any raid like that reported Wednesday would have to be extremely important to risk an almost assured "big backlash" from Pakistan. "You have to consider that something like this will be a more-or-less once-off opportunity for which we will have to pay a price in terms of Pakistani cooperation," the official said. Circumstances surrounding Wednesday's raid weren't clear, but US rules of engagement allow American troops to chase militants across the border into Pakistan's lawless tribal region when they are attacked. They may only go about six miles on the ground, under normal circumstances. US rules allow aircraft to go 10 miles into Pakistan air space. 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. But there has been debate in Washington over how far the US can go on its own. AFP adds: The White House refused Thursday to comment directly on Pakistani anger at a cross-border raid by Afghanistan-based international forces just days before Pakistan's presidential vote. Spokeswoman Dana Perino said US authorities were "working to increase coordination and cooperation and supporting the Pakistanis, as we work to fight against the Taliban in a coordinated way." But Perino met questions about US policy in general regarding cross-border raids inside Pakistan or details of the Wednesday strike, which Islamabad has denounced as "shameful" and unjustified, with a stone wall. "In regards to the reports about that incident, we have not commented, and I won't today," she told reporters. "I'm just not going to comment on the incident in any way." "I will reiterate that we've been working closely with the new civilian government of Pakistan that is feeling its way and working to establish itself," said Perino. She said the two allies faced "a common enemy" in the Taliban militia and the Al-Qaeda terrorist network and noted "a very big scare yesterday" with a failed attack on Pakistan Prime Minister Yousuf Raza Gilani. "We have a lot of cooperation that's ongoing with them and a lot of need to increase communication," said Perino. Asked for the underlying rationale for not commenting on the reported strike, Perino replied: "All I can tell you is that I am going to decline to comment on reports about that incident."