An Afghan soldier shot dead a NATO colleague and was himself killed when a dispute ended in a shoot-out on Sunday, an Afghan security source and the NATO force said.

"At an ISAF base near the governor's office at Zabul (in the south), six ISAF soldiers and three ANA (Afghan National Army) soldiers had a dispute which ended in an exchange of fire," a source of NATO's Afghan security force told AFP.

"An ANA soldier killed a soldier from ISAF. He himself was killed when ISAF opened fire on him," the source added. Others soldiers were wounded in the shoot-out.

An ISAF statement said: "An International Security Assistance Force service member was killed today in southern Afghanistan, apparently by a member of the Afghan National Army."

This is the latest in a string of deadly clashes between ISAF and Afghan soldiers.

On December 24, an Afghan soldier was killed in a gunfight with US troops in southwest Farah province after he opened fire during an argument, Afghan army and police officials said.

Five days later, a man dressed in Afghan army fatigues shot dead two members of France's Foreign Legion serving with ISAF.

On this occasion, the Taliban claimed responsibility, saying the soldier had joined the army in order to carry out his attack in Kapisa province, in the volatile east of the country.

NATO-led ISAF soldiers are in the process of handing over security to local forces before the scheduled withdrawal of all international combat troops by the end of 2014.

Coalition troops often carry out joint operations with Afghan army and police against the Taliban-led insurgency.

For the first time in eight years, the number of Western soldiers killed in Afghanistan dropped in 2011.

It still remains high at 566 killed, but is down from the 2010 toll of 711.