A suicide bomber attacked US and Afghan forces at a checkpoint in a busy market Wednesday in eastern Afghanistan,killing 21 people,including three US soldiers,US and Afghan officials said.
It was the third day in a row the Americans were targeted by insurgents as persistent violence complicates efforts to train Afghans to take over their own security in preparation for the withdrawal of most combat troops at the end of 2014.
Afghan officials initially said a car bomber struck a military convoy,but NATO spokesman Maj. Martyn Crighton,said the attacker hit Afghan and coalition forces at a checkpoint in the city of Khost.
There was a convoy in the vicinity that responded to the attack, Crighton said.
Baryalai Wakman,a spokesman for the Khost provincial government,said the bomber was on foot. There was a motorcycle that was destroyed in the blast but it did not appear to belong to the attacker,he explained.
US Defence Department officials confirmed those killed were Americans and said a suicide vest is suspected to have been used. They spoke on condition of anonymity.
The Afghan presidential palace said 17 Afghans were also killed when they were caught up in the massive blast. Two of the Afghan dead were police officers and the rest civilians,Wakman said. Another 32 people were wounded,all civilians,he said.