The U.S. military in Afghanistan said 20 militants were killed by an airstrike in the Taliban stronghold of Helmand province.
A statement said the airstrike was ordered after Afghan and U.S. led coalition troops were ambushed while on foot patrol in Kajaki district on Wednesday.
The U.S. military said troops made sure there were no civilians in the area before calling in air support.
Southern Afghanistan is the center of a growing Taliban-led insurgency, fueled in part by the illicit opium trade from Helmand's poppy harvests.
The Obama administration has announced a revised strategy to fight militants in Afghanistan and stabilize neighboring Pakistan. The new plan includes the deployment of thousands of additional U.S. troops to Afghanistan and more money to train Afghan police and develop tribal areas.
Some information for this report was provided by AFP and Reuters.