Afghan police say a roadside bomb has exploded in the country's southern province of Helmand, killing four people, including two U.S. nationals.
A provincial police official Sunday said the two Americans, along with their Afghan interpreter and an Afghan police officer, were killed while they were inspecting the bomb in the Naad Ali district.
A Taliban spokesman, Yousuf Ahmadi, told the French News Agency that Taliban militants carried out the attack and killed two American soldiers and several Afghan police.
U.S. officials have not yet confirmed the incident.
Southern Afghanistan is the center of the Taliban-led insurgency, and militants rely heavily on roadside bombs in their campaign against foreign forces.
The United States plans to intensify its fight against the Taliban this year by sending an extra 30,000 troops to Afghanistan.
Some information for this report was provided by AFP and Reuters.