An Afghan man wearing a uniform has shot and killed three US soldiers in the southern province of Helmand, a NATO spokesperson has announced.
The incident took place early on Friday morning, and details were still being gathered, Major Lori Hodge, the spokesperson for the the military alliance in Afghanistan, said.
NATO was looking into whether the attacker was a member of the Afghan military or security forces.
Afghan officials said the men were all special forces members and were killed while attending a meeting in Sangin district.
Mohammed Sharif, the Sangin district chief, put the toll higher, saying that four foreign special forces soldiers had been killed by an Afghan policeman after he had invited them to dinner.
“Last night, a police checkpost commander invited four foreign special forces soldiers to a dinner party at the checkpost. He later killed them and ran away,” Sharif said.
Other Afghan officials confirmed that account.
So-called green on blue shootings, in which Afghan police or soldiers turn their guns on their Western counterparts, have seriously eroded trust between the allies as NATO combat soldiers prepare to hand over to Afghan forces by 2014, after which most foreign forces will leave the country.
According to NATO, there have been 24 such attacks on ISAF troops since January, causing 28 deaths.
Last year, there were 21 such attacks, in which 35 people were killed.
In a separate incident, three US soldiers and a US aid worker were killed on Thursday in the eastern province of Kunar, after a suicide attack.