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WASHINGTON, Feb 8 (Reuters) - Two U.S. service members were killed and six others injured when an individual in an Afghan uniform opened fire on them with a machine gun in eastern Afghanistan, the U.S. military said on Saturday.
The incident, which took place in Nangarhar province, occurred after a combined U.S. and Afghan force completed a "key-leader engagement," Colonel Sonny Leggett, a spokesman for U.S. forces in Afghanistan, said in a statement.
"We are still collecting information and the cause or motive behind the attack is unknown at this time," Leggett added.
Mubariz Khadem, a senior security official in Nangarhar province, told Reuters earlier on Saturday that clashes took place between U.S. and Afghan forces and casualties were feared.
Insider attacks, often known as "green-on-blue" attacks, have been a regular feature of the conflict in Afghanistan, although their frequency has diminished in recent years.
Nangarhar, which shares a long and porous border with neighboring Pakistan, had long served as the main stronghold of Islamic State, from where militants planned and staged bombings around the country, especially the capital Kabul.
The Taliban has also controlled parts of Nangarhar province.
About 13,000 U.S. troops are stationed in Afghanistan as part of the U.S.-led NATO mission to train, assist and advise Afghan forces and to carry out counter-terrorism operations.
The incident comes at a delicate time, as U.S. diplomats have been talking with the Taliban for months to agree a timetable for the withdrawal of foreign forces in exchange for security guarantees.
Despite talks between the United States and the Taliban to end the war, violence in the country has not ebbed. (Reporting by Idrees Ali; Editing by Jacqueline Wong)
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