As US Marines pull back in Helmand province, the Afghan National Army is forced to lead the fight against the Taliban. Al Jazeera looks at the challenges that face one Afghan unit that is battling the Taliban from a remote outpost in the Helmand River Valley.

For another look at how the situation is shaping up in Helmand as the US continues to draw down forces, see Dan Lamothe's article on Helmand. The Taliban are re-infiltrating areas in force as the Marines pull back, seizing territory, seeding roads with IEDs, and conducting attacks on Afghan forces. Some Afghan units are abandoning their posts. An excerpt:

First Battalion, 8th Marines, out of Camp Lejeune, N.C., and 2nd Battalion, 5th Marines, out of Camp Pendleton, Calif., have been withdrawn from Kajaki and Musa Qala respectively. The drawdown left fewer Marines distributed across a broad swath of northern Helmand, Bradney said.

By August, Marine commanders had made it clear to Afghan officers that the Afghan National Army, Afghan Uniformed Police and other native forces would be required to take charge to maintain security.

Marines told them they would remain in advisory roles and provide quick-reaction forces in emergencies but otherwise would launch only occasional operations. It did not take long before the Taliban began attacking the Afghan bases and taking back ground the militancy had lost to the Marines.

Eventually Route 611, the main highway from Sangin to Kajaki, was seeded by militants with explosive devices, and members of the Afghan National Civil Order Police abandoned a number of posts in Sangin, the Marines said.

Afghan commanders asked for help. The Marine commanders initially told them that the Afghan forces had to stand up for themselves but realized they'd better step in if the Taliban was to be halted.