WASHINGTON — The Taliban is confronting a serious “cash flow” problem after losing some half of its annual drug trade money to a farming blight and government eradication efforts, a Marine two-star general said Thursday.

The assessment by Maj. Gen. Richard Mills is a bright spot in an otherwise difficult war involving some 100,000 U.S. troops. American forces for several months have been bogged down in a fight with insurgents in the farming hamlets of Marjah, an area in southern Afghanistan considered at the heart of Afghanistan’s drug trade.

Mills said the insurgency in Marjah is a shadow of what it once was and that the Taliban’s loss in revenue has made it difficult to resupply fighters. But, he added, the Taliban is continuing to terrorize the locals at night and hide explosive devices that are killing U.S. forces and civilians.

“He can’t give Marjah up without a fight, and he hasn’t,” Mills told reporters at a Pentagon news conference.

Mills declined repeatedly to answer questions about when U.S. troops could begin to hand off security operations in Marjah to Afghan forces. He suggested that multiple factors were involved, and while other areas might be secure in “coming months,” Marjah was not likely to be one of them.

“Marjah is still a work in progress, there’s no question.” Mills said. The “starting point” for progress there was “considerably behind some of the other areas” in Helmand province, he said.

President Barack Obama has said U.S. troops will start leaving Afghanistan in July 2011, although the scope and size of withdrawals will depend upon security conditions on the ground.