Afghanistan insider attack kills 5, including 2 Americans

An apparent insider attack in Afghanistan on Saturday has killed five, including a member of NATO-led forces and a civilian contractor.

Details of what happened at the checkpoint of the Afghan National Army (ANA) in the Said Abad district are unclear, but both the governor and police chief of Wardak province, just west of Kabul, said a misunderstanding or argument led to the incident, according to The New York Times. A statement released Sunday by the NATO-led International Security Assistance Force (ISAF) said the attack left a foreign soldier and a civilian contractor dead, but did not identify their nationalities. Afghan officials said they believed they were Americans. Three Afghan soldiers were also killed in the attack.

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"Initial reports indicate that a misunderstanding happened between Afghan army soldiers and American soldiers," provincial government spokesperson Shahidullah Shahid said, noted Newsday.

The Times also gave the account of an anonymous Afghan official, who said a mortar shell that landed amid American forces had killed the soldier and contractor. The Americans thought it had come from the ANA and attacked it in retaliation.

The deadly attack came after joint operations between the US and Afghanistan were returning to normal, reported Reuters. They had been put on hold just two weeks before after a surge of attacks on the ISAF by its Afghan allies. At least 52 ISAF members have been killed in 2012 in "green-on-blue" attacks. Officials said it was too early to tell how Saturday's attack would affect relations between the two countries' forces.