KABUL: Three men in Afghan police uniforms killed a soldier with the US-led Nato coalition on Monday, the coalition said, in the latest so-called “green-on-blue” attack.

The three attackers fled after the killing, Nato’s International Security Assistance Force (Isaf) said in a statement, and are being sought.

The death takes the toll this year in “green-on-blue” attack, in which Afghan forces turn their weapons against their Western allies, to 23, in a total of 17 such incidents.

“The International Security Assistance Force confirms that three individuals in Afghan police uniforms turned their weapons against coalition service members in southern Afghanistan yesterday, killing one Isaf service member,” Isaf said.

A police source in southern Kandahar province said two Nato soldiers were killed when the police opened fire on them.

Following its normal policy, Isaf gave no further details of the incident or the soldiers’ nationalities.

Monday’s attack is the first time men in Afghan uniforms have killed Nato soldiers since two Afghan police officers killed two British soldiers in southern Helmand province in May.

An increasing number of Afghan troops have turned their weapons against Nato soldiers who are helping Kabul fight a decade-long insurgency by hardline Taliban militants.

Some of the assaults are claimed by the Taliban, who say they have infiltrated the ranks of Afghan security forces, but many are attributed to cultural differences and antagonism between the allied forces.

Isaf has taken several security measures in response to the shootings, including assigning “guardian angels”, soldiers who watch over their comrades as they sleep.

Nato has around 130,000 soldiers fighting alongside some 350,000 Afghan security personnel against the Taliban-led insurgency, but they are due to pull out of the country in 2014.

The Western coalition is to hand over security in the war-torn country to local forces by mid-2013 and will play a support role up to the final withdrawal by the end of 2014.