Further, the plan to turn to irregular forces is stoking anxieties of factional rivalries and civil strife in a nation still haunted by a civil war in the 1990s in which feuding militia commanders tore the country apart. Some of the commanders involved in that bloodletting a generation ago now hold senior government positions and are encouraging the current effort to mobilize and rearm militias.

“We have experienced this failed experiment of militia-making before,” said Fawzia Koofi, a member of Parliament from Badakhshan, one of the provinces where the government is planning to form the militias. “This will spread the war from house to house, starting rivalries as everyone begins arming their own groups.”

The establishment of the Afghan military and police forces, which are said by officials to number more than 320,000 members as of late last year, has been held up as one of the signal accomplishments of the United States-led presence here. By many accounts, the forces have continued to fight effectively in a number of areas across the country, even with far less of the air support and logistical assistance that the United States had been providing in past years.

But the Afghans are taking casualties at an alarming rate.