In the March 4 ambush, the Marines were traveling in a convoy on a highway in Nangarhar province when they were hit with a car bomb followed by small arms fire, and fired back in self-defense, according to U.S. military accounts. Afghan witnesses said the Marines fired recklessly at passing vehicles and pedestrians along the crowded road flanked by shops.

The U.S. military initially said 16 civilians were killed but later changed that estimate to eight. An official at a local hospital said 14 people had died. The military said 35 people were wounded, among them a coalition service member.

Afghan President Hamid Karzai criticized the U.S. military reaction, and the incident sparked large anti-American protests.

Kearney ordered an Article 15-6 investigation, in which an investigating officer conducts an inquiry and reports back to the commander, to begin soon afterward, Leto said.

The investigation and abrupt removal of the unit, known as MSOC-F, is doubly significant because the company was composed of some of the most experienced, highly trained Marines ? including many experts in reconnaissance and marksmanship. Their focus, however, is on killing and capturing targets, in contrast to that of other elite troops who specialize in working with indigenous forces.