ISLAMABAD, Sept 26: Pakistan warned US troops on Friday not to intrude into its territory after the two anti-terror allies traded fire along the Afghan border on Thursday.

The five-minute clash — the first serious exchange with Pakistani forces acknowledged by the US — came at a time the United States is stepping up cross-border operations in Pakistan’s frontier region.

Government spokesman Akram Shaheedi urged US-led coalition forces “not to violate territorial sovereignty of Pakistan as it is counter-productive to the war on terror”.

“It has been Pakistan’s policy that we will not allow anyone to violate our sovereignty, and we will continue to defend our territorial sovereignty,” he said.

NATO PROBE: The Nato-led force in Afghanistan said it was trying to establish what led Pakistani forces to fire on two US helicopters, repeating that the choppers had not crossed the border.

“Clearly it is a misunderstanding,” said Brigadier General Richard Blanchette, spokesman for Nato’s International Security Assistance Force, in Kabul.

“Isaf and the Pakistan military are trying to see through what happened,” he told AFP. “We are trying to calm down the waters, because we don’t want this to become more complicated than it has to be.”—Agencies