A spokesman for the alliance, Lieutenant-Colonel David Reynolds, said the fighting to retake the town of Garmsel in Helmand Province involved 200 Afghan government troops backed by Danish, British, and Estonian soldiers.
Meanwhile, Afghanistan's Deputy Border Affairs Minister Asadullah Wafa told Radio Free Afghanistan that the Taliban have captured two districts in the southwest of the country.
His comments confirm a claim made to Radio Free Afghanistan earlier on September 12 by a man who introduced himself as a spokesman for the Taliban, Qari Yusaf Ahmadi, that the armed Islamic militia had taken control of the district of Dilaram in Nimroz Province and Farah Rud district in Farah Province.
Nimruz and Farah provinces border Iran.
In separate incidents, Afghan security forces killed six Taliban rebels and captured 14 others in operations in eastern and southern Afghanistan.
The Interior Ministry said four militants were killed in a battle with Afghan troops in the Zurmat district of the eastern province of Paktia on September 11.
Officials said that those detained included nine people accused of arranging suicide bombings.