A suicide bomber blew himself up outside a school in Samkani district of Paktia province, 100 km south of the Afghan capital of Kabul, killing 11 people including the attacker and injuring 17 others on Monday, provincial police chief Zalmai Oryakhil said.
"The terrorist riding an explosive-laden motorbike and blew himself up next to a school when some U.S. soldiers were passing by, killing himself and 10 others, mostly school children and injuring 17 others," Oryakhil told Xinhua.
Two American soldiers and 14 civilians were among those injured in the deadly attack, he added.
No groups or individual have claimed responsibility for the attack.
However, Orhakhil blamed the attack on the enemies of peace, an official reference to Taliban militants.
Taliban, which launched so-called spring offensive on April 28 against the government and foreign forces, has yet to make comment.