An attack on US troops in 2007 that left an American officer dead was the act of a rogue Pakistani gunman and not a plot by the country's military, according to a US probe released Monday.

For years, details of the shooting on Pakistan's border with Afghanistan have been shrouded in secrecy amid speculation US officials were anxious to avoid aggravating tensions with Pakistan.

A US military investigation into the shooting had remained secret until Monday.

The Pentagon released a two-page unclassified excerpt from the probe into the May 14, 2007 shooting, in which US Major Larry Bauguess was killed when a militia member opened fire on American officers who had just finished a meeting with their Pakistani and Afghan counterparts.

The probe concluded that Bauguess was shot at close range with a volley of AK-47 automatic fire by a man wearing a militia uniform from Pakistan's Frontier Corps, which is stationed along the Afghan border.

But there was no proof that the shooter was helped by Pakistani forces, it said.

"There is little evidence to support collaboration within the Pakistani militia or military," said the report.

"The initial shooter caused all of the casualties incurred on the (NATO-led) coalition forces," it added.

The probe found no sign of coordinating fire from Pakistani forces in support of the gunman.

However, some "sporadic" fire from the Pakistani troops was likely a response to cover fire from US troops trying to withdraw from the area to a helicopter landing zone, the report said.

The 10-minute gun battle that erupted after the shooting by the gunman left seven Pakistanis dead, it said.

The investigation appeared to contradict an extensive New York Times report last month that suggested the Americans and Afghans had been targeted in an ambush in collaboration with Pakistani forces, possibly in retaliation for previous incidents in which Pakistani troops were mistakenly fired on by US forces.

The Times' account quoted Afghan officers who witnessed the shooting as well as US military officers and an unnamed UN source.

An Afghan officer at the meeting, Colonel Sher Ahmed Kuchai, told the newspaper that senior Pakistani officers left the meeting place minutes before the shooting erupted without saying goodbye, which he believed showed they knew an attack was coming.

The meeting that preceded the shooting was held in Teri Mangal in Pakistan's Kurram agency and had been arranged after Afghan and Pakistani forces traded fire in a growing border dispute.

The Pakistanis had objected to a new border outpost set up by Afghan forces, which Islamabad charged was on Pakistani territory.