A suicide bomber has attacked a joint Afghan-NATO patrol in eastern Afghanistan, killing at least 14 people.

NATO says the deaths Monday include three coalition service members and their interpreter. It did not identify the nationalities of the soldier or provide further details on the attack.

Local officials say the bomber rammed a motorcycle into the patrol near a market in the city of Khost. They say the attack also killed six civilians and four police officers.

The Taliban claimed responsibility for the bombing.

Meanwhile, NATO and Afghan officials are investigating a gunbattle Saturday that killed two Americans and three Afghan soldiers. The two sides have given conflicting accounts of that incident, which came days after U.S.-led coalition forces eased restrictions on joint operations with their Afghan allies.

NATO initially described the gunbattle as a suspected “insider attack,” in which Afghan security forces or insurgents disguised as them open fire on NATO personnel. But the NATO coalition's deputy commander, Lt. Gen. Adrian Bradshaw, later told a Sunday news conference that “insurgent” fire may have played a role in the fighting.

NATO also said the gunbattle began after a “short conversation” between Afghan security forces and coalition troops who were manning a temporary checkpoint nearby.

The Afghan Defense Ministry said the exchange of fire was the result of a “misunderstanding” between the two sides, an account that left open the possibility of an insider attack. Such attacks have escalated this year, killing at least 52 coalition personnel.