KABUL: Pakistani troops fired at two NATO-led US helicopters operating in eastern Afghanistan, the international force said, adding that there was no damage or casualties.
The Pakistani military said troops fired warning shots at two NATO helicopters after they crossed the border from Afghanistan on Thursday, adding that the choppers returned fire.
'Two helicopters crossed into our territory in Ghulam Khan area. They passed over our checkpost so our troops fired warning shots,' chief Pakistani military spokesman Major General Athar Abbas told AFP.
'The helicopters returned fire but there was no damage on the ground.'
Abbas added that the matter was being taken up with the NATO-led International Security Assistance Force in Kabul through the usual channels between the force and the Pakistani military.
A separate military statement said the helicopters were 'well within Pakistani territory' when the incident happened.
The NATO-led force in Afghanistan earlier said Pakistani troops at a military checkpost opened fire on the helicopters but insisted they were in Afghan airspace at the time.
The International Security Assistance Force (ISAF) stressed that the helicopters had not crossed into Pakistani airspace.
'ISAF helicopters received small-arms fire from a Pakistan military checkpoint along the border near Tanai district, Khost, September 25 while conducting routine operations in Afghanistan,' it said in a statement.
'There are no reports of any damages to the helicopters or any casualties.
With tensions high, the Pentagon quickly called Thursday's events 'an unfortunate misunderstanding' and confirmed US helicopters were involved.
'They are confident that they were in Afghan air space the whole time,' said Bryan Whitman, a Pentagon spokesman.
Separately, Tech Sgt. Kevin Wallace, a US military spokesman, said Pakistani troops fired at American reconnaissance helicopters patrolling along the Afghan-Pakistan border Thursday, but there was no damage to aircraft or crew.
Two American OH-58 reconnaissance helicopters, known as Kiowas, were on a routine patrol Thursday in the eastern province of Khost when they received small arms fire from a Pakistani border post, Wallace said.
'They did not cross the border and they did not fire back,' he said.
In Washington, a US official said the incident occurred Thursday afternoon Pakistan time.
Local residents said one of the two helicopters had entered inside Pakistan territory by a kilometer and a half, while the other hovered on the Afghan side.
'When our forces fired warning shots, we were a little scared of a possible retaliatory fire from the helicopters. But we were happy to see the helicopter flying back into Afghanistan. We were happy that our forces fired at the helicopter,' a resident said.
On Wednesday, Pakistan's army said it had found the wreckage of a suspected surveillance drone in South Waziristan, but denied claims by Pakistani intelligence officials that troops and local people shot down the aircraft.
However, a US military official, speaking on condition of anonymity, said that the drone might have been operated by the CIA.
Tensions across the rugged and porous border are high after a series of US missile strikes on al-Qaeda-linked militants and an incursion by US soldiers into Pakistani tribal areas adjoining Afghanistan.