Updated

Several hundred U.S. Marines engaged in a dramatic firefight Tuesday with an army of rebels in a Taliban stronghold in southern Afghanistan.

The battle against insurgents came during the first large-scale American operation in the area in years.

Hundreds of Marines charged into the Taliban-held town of Garmser before dawn Tuesday, reported FOX News' Dana Lewis — who is embedded with the 24th Marine Expeditionary Unit that led the mission.

Click here to see Dana Lewis' report.

Many of the 2,300-member unit who conducted the operation are Iraq war veterans. Their goal: to drive out militants and expand NATO's reach to cover a region that's been classified as Taliban territory and is blanketed with opium poppy fields.

U.S. commanders said Taliban fighters were expecting an assault and planted homemade bombs in response.

The British have a small base on the town's edge but Garmser's main marketplace is closed because of the Taliban threat.

Marines moved into town by helicopter and Humvee for Tuesday's assault in the southern province of Helmand, the first major task undertaken by the 2,300 Marines in the 24th Marine Expeditionary Unit.

The unit arrived last month from Camp Lejeune, N.C., for a seven-month deployment. Another 1,200 Marines also came to train Afghan police.

Maj. Tom Clinton, the American commander at Forward Operating Base Dwyer, a British outpost 10 miles west of Garmser, said militants and Marines exchanged fire in two parts of Garmser on Tuesday. There was no immediate word on casualties.

"We haven't seen anybody who isn't carrying a gun," Clinton said of the mostly deserted town. "They're trying to figure out what we're doing. They're shooting at us, letting us know they're there."

Clinton, 36, of Swampscott, Mass., said Marines had also found bomb-making material and rockets in town. He said he was worried about the possibility of attacks using homemade bombs.

The Marines' mission is the first carried out by U.S. forces this far south in Helmand province in years. An operation late last year to take back the Taliban-held town of Musa Qala on the north end of Helmand involved U.S., British and Afghan forces.

Helmand province is the world's largest opium poppy growing region and has been a flash point of the increasingly violent insurgency in the last two years. British troops — who are responsible for Helmand — have faced fierce battles on the north end of Helmand.

Most U.S. troops operate in the east, along the border with Pakistan, but Britain, with 7,500 troops, and Canada, with 2,500 troops in neighboring Kandahar province, have not had enough manpower to tame the south.

More than 8,000 people died in insurgency-related violence last year. Militants set off more than 140 homicide bombs. Taliban fighters have been increasingly relying on roadside bombs and homicide attacks after being routed in force-to-force battles in the past.

The Marines had prepared on Monday by cleaning weapons and handing out grenades. The leader of one of the three companies involved — Charlie Company commander Capt. John Moder — said his men were ready.

"The feeling in general is optimistic, excited," said Moder, 34, of North Kingstown, Rhode Island. "They've been training for this deployment the last nine months. We've got veteran leaders."

Many of the men in the 24th Marine Expeditionary Unit served in 2006 and 2007 in Ramadi, the capital of Anbar province in western Iraq. The vast region was once the stronghold of Al Qaeda in Iraq before the militants were pushed out in early 2007.

Moder said that experience would affect how his men fight in Afghanistan. "These guys saw a lot of progress in Ramadi, so they understand it's not just kinetic (fighting) but it's reconstruction and economic development."

But on the initial assault, Moder said his men were prepared to face mines and homemade bombs and "anybody that wants to fight us."

One Marine in Charlie Company, Cpl. Matt Gregorio, 26, from Boston, alluded to the fact the Marines had been in Afghanistan for six weeks without carrying out any missions. He said the mood was "anxious, excited."

"We've been waiting a while to get this going," he said.

The Associated Press contributed to this report.