An Afghan soldier on Saturday opened fire on his NATO partners in Kabul, wounding a NATO soldier in the latest in a series of "insider" attacks on alliance forces, officials said.

Attacks in which Afghan forces turn their guns on their international partners have killed scores of NATO-led troops, breeding mistrust and undermining efforts to train local forces before NATO combat troops withdraw next year.

"An Afghan army soldier opened fire on NATO troops in Kabul, wounding a NATO soldier on his leg," defence ministry spokesman general Zahir Azimi told AFP.

"The attacker was killed when NATO soldiers returned fire, the incident is under investigation," he said, adding that it happened inside a base.

A NATO spokesman in Kabul confirmed the incident but would not provide more details.

The bulk of around 87,000 US-led NATO troops who are stationed in Afghanistan as part of the war on terror campaign are scheduled to withdraw in 2014.