Early this morning, US helicopters crossed the border into Pakistan’s South Waziristan Agency and attempted to land in Angor Adda, in a raid reminiscent of September 3rd’s unprecedented attack by US helicopters and ground forces in the same region, which killed 20 civilians. This was seen as the beginning of America’s so-called “gloves are off” strategy of escalating attacks along the Pakistani border. But this incident ended quite differently from the previous raid.

Pakistan’s Chief of Army Staff Parvez Kayani announced last week that the Pakistani military would no longer allow foreign forces to operate on Pakistani soil. On Thursday, another high ranking Pakistani official, Major-General Athar Abbas confirmed the order, and said the army had been ordered to retaliate against foreign operations. If the Bush Administration was unclear on the sincerity of this position prior to today, it is no doubt clarified as Pakistani troops opened fire on the invading helicopters, forcing them to retreat into Afghanistan.

Officially, Pakistan’s military denies that the Americans ever crossed the border or that their forces fired on them, but several news agencies cite local officials and anonymous military personnel who confirm the incident. One of the local residents told DPA that they had advanced warning of the impending American attack, and that “thousands of armed tribesmen” had amassed on the Pakistani side of the border intent on fighting them off.

The latest border incident comes with newly elected President Asif Ali Zardari en route to Britain for talks with Prime Minister Gordon Brown. Brown has said that he will press Pakistan to allow NATO forces into its territory, though NATO has insisted that it won’t participate in any US cross-border raids.

President Zardari announced in an editorial published the day after the first Angor Adda attack in the Washington Post that he “stands with the United States,” a position that seems increasingly untenable as the unpopular US air strikes continue and tribesmen in the South Waziristan area threaten to abandon a long-standing peace deal if his government doesn’t end the US attacks on them.