NATO says a man in an Afghan police uniform has shot dead three international coalition personnel in the war-torn country's troubled south.
NATO's International Security Assistance Force (ISAF) gave few details of the incident and did not reveal the nationality of the victims.
An ISAF spokesman said the gunman was injured and arrested after the attack. He added that ISAF was still investigating whether the attacker was a police officer or not.
An increasing number of Afghan troops have been turning their weapons against NATO soldiers.
Earlier, Afghan police said a roadside bomb killed five Afghan civilians in eastern Ghazni Province.
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.
Based on reporting from AFP and AP