U.S. military spokesmen say four American soldiers have been wounded by an insurgent's roadside bomb that hit their armored vehicle in northeastern Afghanistan.

The troops were attacked as they returned from defusing another bomb near Asadabad town, in Kunar province.

A military statement says the wounded were evacuated to Bagram Air Base, north of Kabul, where they are in stable condition.

The statement also says U.S. and Afghan troops have begun a search "to kill or capture those responsible."

Similar attacks in the past have been blamed on the Taleban, which was ousted by a U.S.-led invasion four years ago.