'Insider attack' kills 2 Americans in Kabul

Two Americans including a civilian were killed when a gunman opened fire near a Nato base in Kabul yesterday, the military coalition said, with Afghan officials calling it an "insider attack".

No insurgent group has so far claimed responsibility for the attack, which highlights growing insecurity in Afghanistan as the Taliban step up their nationwide insurgency.

"One US service member and one US civilian died as a result of wounds sustained in Kabul today," Nato said in a statement, adding that three other Americans were wounded in the incident.

"The two individuals were killed during an attack near a coalition base by an unknown assailant, who was later killed."

An American official said the shootout occurred at a military ammunition supply point near Camp Morehead, a base used for Afghan commando training.

Defence ministry spokesman Dawlat Waziri earlier indicated it was a so-called insider attack, saying one Nato soldier had been killed and five others were wounded by a gunman wearing military uniform.

Nato said the Americans were conducting duties as part of their mission to train, advise and assist Afghan forces when they came under attack, adding that an investigation had been launched into the incident.

So-called "green-on-blue" attacks -- when Afghan soldiers or police turn their guns on international troops -- have been a major problem during NATO's long years fighting alongside Afghan forces.