Afghan troops have been slowly pushing up through a fertile river valley in the southern Helmand province, with special forces mounting nighttime helicopter raids into mud brick compounds and ground troops gradually advancing across the poppy fields that in past years have furnished the insurgents' main cash crop.
US and British troops suffered some of their biggest losses of the decade-long war here, seizing territory that was later lost by ill-equipped and poorly trained Afghan forces.
Ghani was personally involved in planning the operation, which is codenamed Zolfiqar meaning double-edged sword and which began on February 10, according to Maj. Gen. Kurt Fuller, deputy chief of staff for US and NATO operations in Afghanistan.
Ghani heads to Washington later this month, where he is expected to seek enhanced US military backup, particularly air support.
"This is an incredibly important operation," said a Western diplomat who spoke on condition of anonymity in order to discuss the secret operation.
US and Afghan officials say local security forces are so far proving they can take the fight to the Taliban without the aid of foreign combat troops.
There are 13,000 foreign soldiers in the country, down from a peak of 140,000 in 2009-2010, with 5,000 US troops engaged in counterterrorism operations against the Taliban and al-Qaida.
US military leaders have advised the troops in Helmand and helped plan the operation, but American troops are not involved in the fighting.
He said Afghan forces had found bunkers, tunnels, trench lines, and a giant slingshot apparently used to fling grenades at government forces.
He said the Sangin district, which had seen months of heavy fighting, was declared clear on Friday, adding that Afghan forces had "met with heavy resistance that was more than they anticipated.
