Pakistan warns US troops after exchange of fire

Pakistan warned US troops not to intrude on its territory Friday, after the two anti-terror allies traded fire along the volatile border with Afghanistan. Thursday's five-minute clash adds to already heightened tensions at a time the United States is stepping up cross-border operations in a region known as a haven for Taliban and al-Qaida militants. The clash - the first serious exchange with Pakistani forces acknowledged by the US - follows a string of other alleged border incidents and incursions that have angered many Pakistanis. Speaking in New York, Pakistan's president tried to play down the incident, saying only "flares" were fired at foreign helicopters that he said strayed into his country from Afghanistan. US and NATO military officials said the ground troops and helicopters were in Afghan territory.