July 3, 2009 U.S. troops waging fierce battle in Afghanistan Play video

(NECN/ABC) - Fierce fighting and the first casualties were had Friday morning as U.S. Marines conducted a major offensive in Afghanistan.

It is a struggle to break the Taliban's grip on Helmand province, notorious for its opium trade, and a cash machine for terrorism.

The fight to win this territory away from the Taliban is tough and fraught with danger.

This operation, the largest mounted by U.S. Troops since 2001, as thousands of U.S. Marines fanned out across the lower Helmand River Valley. One U.S. Marine was killed and several others were wounded.

Helmand province is an area notorious for being a Taliban stronghold, where in recent years they have ruled with terror and fear.

Correspondent Mike Boettcher embedded on the frontlines, described what the troops were up against.

"We learned that the Taliban is not going to give this piece of Afghanistan up easily," Boettcher said. "All day long, we were under harassing automatic weapons fire, sniper fire, occasional mortars and IEDs in plowed fields."

This province is as lawless as it gets. It is the biggest producer of opium poppies in the country, which in turn accounts for 90 percent of the world's heroin and, for the U.S., this operation this will be crucial to living up to its promise to help the Afghan government gain control of this area ahead of the elections.

This is also a crucial test for the Obama administration's new strategy to defeat extremism

In a separate incident, an American soldier has been captured by militants in eastern Afghanistan. He went missing on Tuesday in Paktika province.

The details surrounding his disappearance are still sketchy, but there is a an ongoing search for the soldier, who was off-duty when he vanished.

He was only discovered missing in the morning when his bulletproof body armor and rifle were found at the base.

ABC's Sonia Gallego reports.