Six U.S. soldiers killed in suicide bomb attack near Afghanistan's Bagram Airfield

KABUL, Afghanistan, Dec. 21 (UPI) -- A suicide bomber on a motorbike attacked a joint U.S.-Afghan patrol near the Bagram Airfield, killing at least six U.S. soldiers in Afghanistan's Parwan province

A U.S. military official in Afghanistan confirmed the troops killed were all American, The Washington Post reported. Parwan governor spokesman Waheed Sediqqi confirmed the attack to CBS News.

Taliban spokesman Zabihullah Mujahid claimed claimed responsibility for the attack on Twitter.

NATO's Afghan coalition spokesman U.S. Army Col. Michael Lawhorn said there was "vehicle-borne improvised explosive device attack" that was under investigation. The identities and nationalities of those killed or injured have not yet been determined.

Bagram Airfield is about 25 miles northeast of Kabul, the Afghan capital, and is one of the main bases for U.S. troops.

Brig. Gen. William Shoffner, head of public affairs at the Resolute Support base in Kabul, confirmed the deaths.

"We're deeply saddened by this loss," Shoffner said, BBC News reported. "Our heartfelt sympathies go out to the families and friends of those affected in this tragic incident, especially during this holiday season."