Washington, Sept. 25: Pakistani and American ground troops exchanged fire along the border with Afghanistan today after the Pakistanis shot at two American helicopters.

The two OH-58 Kiowa reconnaissance helicopters were not damaged and no casualties were reported on either side from the ground fire. But American and Pakistani officials agreed on little else about what happened in the fleeting mid-afternoon clash between the allied troops.

American and Nato officials said that the two helicopters were flying about one mile inside Afghan air space to protect an American and Afghan patrol on the ground when the aircraft were fired on by small-calibre arms fire from a Pakistani military checkpoint near Tanai district in Khost province.

In response, the American ground troops shot short bursts of warning fire, which hit well shy of the rocky, hilltop checkpoint. The Pakistanis fired back, said Rear Admiral Gregory Smith, a spokesman for the Central Command.

But a spokesman for the Pakistani army, Major General Athar Abbas, said Pakistani forces fired warning shots at the American aircraft after they crossed into Pakistan’s territory in Saidgai, North Waziristan’s Ghulam Khan region. “After this, the helicopters returned fire and flew back,” Abbas said.

Local residents said that one of the two helicopters had entered inside Pakistan territory by about a mile, while the other hovered on the Afghan side of the border.

“When our forces fired warning shots, we were a little scared of a possible retaliatory fire from the helicopters,” said one of the residents, Haji Said Rehman Gorbaz. “But we were happy to see the helicopter flying back into Afghanistan.”