Helicopter-borne U.S. Marines backed by Harrier jets stormed into a strategic Taliban-held town in southern Afghanistan before dawn Wednesday, battling to gain control of the area ahead of next week''s presidential elections.

Associated Press journalists traveling with the first wave said Marines were met with small arms, mortar and rocket propelled grenade fire as they flew in helicopters over Taliban lines and dropped into the town. Fighting was still under way hours later, with U.S. Marine Harrier jets streaking overhead and dropping flares in a show of force.

Other Marines met heavy resistance as they fought to seize control of the mountains surrounding Dahaneh in the southern province of Helmand. Another convoy of Marines rolled into the town despite roadside bomb attacks and gunfire.

It was the first time NATO troops had entered Dahaneh, which has been under Taliban control for years. Casualty figures were unavailable due to security restrictions.

U.S., NATO and Afghan troops are working to protect voting sites around the country so Afghans can take part in the country''s second-ever direct presidential election. Taliban militants have vowed to disrupt the elections, and attacks are on the rise around Afghanistan.