Afghan pilot opens fire on military base

A soldier guards the Afghan air force compound in Kabul, where an Afghan pilot killed two NATO troops during a dispute.

Kabul, Afghanistan (CNN) — At least six American service members were killed Wednesday when a man opened fire on troops and a “gunfight” ensued at an airport in the Afghan capital, military officials said.

A NATO official backed off earlier reports that eight coalition service members and a contractor were killed, saying that the alliance could only confirm six International Security Assistance Force (ISAF) troops were killed. It did not disclose their nationalities.

The incident — which occurred at the Afghan national air force compound at North Kabul International Airport — stems from an argument between an Afghan pilot and an international colleague, officials said.

“A 50-year-old man opened fire at armed U.S. military soldiers inside the airport after an argument between them turned serious,” said Col. Baha Dur, chief of public relations for the Afghan National Army at Kabul military airport.

NATO said the confrontation took place at 10:25 a.m. at North Kabul International Airport, where a quick reaction force responded to a “small arms fire incident.” The airport is home to NATO Air Training Command Afghanistan.

An ISAF spokesman said the incident was “still ongoing.”

The Taliban claimed responsibility for the shooting, saying a man named Azizullah was responsible.

“One suicide attacker … managed to attack an Afghan military unit and has managed to kill many Afghan and international soldiers,” said Taliban spokesman Zabiullah Mujahid.

The Taliban said the man killed nine foreigners and five Afghans before being killed by the Afghan army.

“All I can tell you now is that we had worked hard on this plan for a long time,” Mujahid told CNN.

NATO denied the Taliban claim.

“We do not know why it started but there is no indication that a suicide bomber was involved and there are no reports that someone managed to get into the base to do this,” an ISAF statement said.

The Taliban has claimed responsibility for previous conflicts between NATO service members and members of the Afghan military. CNN could not independently verify the group’s claims.

Violence between Afghan forces and NATO troops is a matter of extreme concern for NATO officials, and it is growing in frequency.

There have been 36 NATO deaths in the past two years attributed to attacks by people perceived to be Afghan soldiers or police. Officials fear that the increasing frequency of the attacks could undermine trust between NATO troops and the Afghans they are working hard to prepare so they can eventually take over security in the country.

While the details of the airport incident remain unclear, the Taliban’s claim that the Afghan gunman was their recruit follows a now familiar pattern of the insurgency stating that attacks are theirs, even though NATO later suggests the gunman was acting out of personal motivation.

Out of 16 incidents of Afghan forces shooting NATO personnel that NATO has investigated, eight have been determined to be motivated by combat stress on the part of the Afghan attacker. The other eight investigations are undetermined.

CNN’s Joe Sterling contributed to this report