Marines battle to oust Taliban from southern Afghanistan

KABUL, Afghanistan (CNN) - U.S. Marines engaged in sporadic fighting for a second day Friday against entrenched Taliban militants in southern Afghanistan, Marine Capt. William Pelletier said.

Helmand province, a poppy-growing region, is the focus of the U.S.-led Operation Khanjar, or Strike of the Sword. Afghanistan supplies 90 percent of the world's opium - which is used in the production of heroin. Most of the revenue supports the Taliban.

U.S.-led forces are targeting key population centers - primarily Garmser and Nawa districts in central Helmand and Rig district in the south, Pelletier said.