The operation will involve about 4,000 troops from the 2nd Marine Expeditionary Brigade, which was dispatched to Afghanistan earlier this year by President Obama to combat a growing Taliban insurgency in Helmand and other southern provinces. The Marines, along with an Army brigade that is scheduled to arrive later this summer, plan to push into pockets of the country where NATO forces have not had a presence. In many of those areas, the Taliban have evicted local police and government officials, and taken power.

Once Marine units arrive in their designated towns and villages, they have been instructed to build and live in small outposts among the local population. The brigade’s commander, Brig. Gen. Lawrence D. Nicholson, said his Marines will focus their efforts on protecting civilians from the Taliban, and on restoring Afghan government services, instead of a series of hunt-and-kill missions against the insurgents.

“We’re doing this very differently,” Nicholson said to his senior officers a few hours before the mission began. “We’re going to be with the people. We’re not going to drive to work. We’re going to walk to work.”