Kabul, Afghanistan (CNN) -- Eight U.S. service members and an American civilian contractor were killed Wednesday in a shooting at an Afghan air force compound in Kabul, officials said. The NATO-led International Security Assistance Force in Afghanistan said an Afghan military pilot opened fire on international troops, sparking a "gunfight." The Taliban, however, claimed responsibility for the attack and said it had been working with the shooter for some time -- an assertion that NATO denied. Also denying the Taliban claim was the brother of the pilot. "My brother had no connections with the Taliban, and I deny any claims of his connection by the Taliban," Dr. Mohammad Hosain Sahebi told a local Afghan TV station in a telephone interview.
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NEW: U.S. military official: A report says the shooting occurred in a meeting room
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NEW: Two additional NATO troops are killed in separate attacks
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The nine slain at the air force compound were Americans, the Pentagon says
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The Taliban claims responsibility for the shooting
Later Wednesday @placeholder announced that two additional service members were killed in attacks elsewhere in the country, bringing the day's total number of NATO casualties to at least 11.
Out of 16 incidents of Afghan forces shooting @placeholder personnel that NATO has investigated, eight have been determined to be motivated by combat stress on the part of the Afghan attacker.