A suicide bomber on a motorcycle attacked a joint US-Afghan patrol in Afghanistan on Monday, killing at least six foreign soldiers, NATO said.
A US official, speaking on condition of anonymity as he was not authorized to speak to the press, told the Associated Press that American troops were among those killed in the attack near Bagram Airfield, the largest US military facility in Afghanistan.
It is the deadliest attack on foreign troops since August.
Brig Gen Wilson Shoffner, head of public affairs at NATO's Resolute Support base in the Afghan capital Kabul, said in a statement that six members of its Resolute Support mission were killed and three others were wounded in the attack.
“We're deeply saddened by this loss," said Shoffner.
NATO did not confirm the nationalities of the casualties, in accordance with its normal practice.
Earlier, an Afghan official put the number of NATO personnel dead at three, with another two wounded.
Taliban spokesman Zabihullah Mujahid claimed responsibility on Twitter and said 19 soldiers had been killed and a number wounded.