Pakistan troops open fire on US helicopters

Tensions between Pakistan and America rose sharply today after the US military said US and Afghan forces had exchanged gunfire with Pakistani troops.

A five-minute gun battle broke out on the border with Afghanistan after Pakistani soldiers fired warning shots at two US helicopters. No one was hurt and the US maintained its troops did not cross the border from Afghanistan.

Cross-border action by US-led forces has angered Pakistan in recent weeks. The latest took place along the Pakistani border with the eastern Afghan region of Khost, a hotbed of militant groups.

Forces from the US-led coalition and the Nato-led International Security Assistance Force patrol the frontier but Pakistan-has been angered by missile strikes by its Western ally and operations across the border in pursuit of insurgents. The US made a commando raid on 3 September on a village in South Waziristan.

At the United Nations in New York last night, Pakistan's president Asif Ali Zardari said: "Just as we will not let Pakistan's territory be used by terrorists for attacks against our people and our neighbours, we cannot allow our territory and our sovereignty to be violated by our friends."

In Washington, a Pentagon spokesman insisted the helicopters had not entered Pakistan. He described the gun battle as "troubling" and called on Islamabad for an explanation.

"The flight path of the helicopters at no point took them over Pakistan," he said. "The Pakistanis have to provide us with a better understanding of why this took place."

According to Pakistan's military, its soldiers fired warning shots at two US helicopters after they intruded into its airspace.

The US military said the helicopters were protecting a patrol about one mile inside Afghanistan.