Updated 9/25 3:55 PM EST

NATO has issued a statement today saying that Pakistan troops opened fire on two helicopters near the Afghan border. This is the third such incident reported in the past two weeks, with the other two reports involving US helicopters in South Waziristan. This report is unique, however, in that it did not come from anonymous officials over the denials of their military, but rather was an official statement issued by NATO itself later confirmed by the US military.

According to a US military spokesman the helicopters were two American OH-58 reconnaissance helicopters, and they received small arms fire from a Pakistani border post. He insists “they did not cross the border and they did not fire back.” The incident occurred in the Khost Province, which is directly across the border from North Waziristan. Pakistani President Asif Ali Zardari said his military only fired flares to warn the helicopters that they had crossed the mountainous border.

The United States launched two air strikes into North Waziristan earlier this month, killing 23 and 14 people, respectively. A third air strike was briefly reported, but that strike turned out to be on the tiny village of Al Must, just across the border in Afghanistan.

The Pakistani military has barred foreign forces from operating inside its territory since shortly after an incident in which US forces killed 20 civilians in South Waziristan. According to Major-General Abbas, the army has been authorized to retaliate against any incursions by foreign troops.