The guidelines also instruct commanders to coach troops to not “automatically take the easy safe route when doing so requires the use of standoff weapons or indirect fire,” and to practice drills “that include decisions to disengage, as well as decisions to engage.” Troops are also told to construct checkpoints more carefully to give more space to maneuver and potentially avoid shooting at vehicles perceived as threatening.

Teams are being sent to stress the new rules to ground units. General Rodriguez’s senior enlisted counterpart, Command Sgt. Maj. Darrin J. Bohn, said teams were emphasizing that procedures that made sense in one area would not necessarily work in others, and that local commanders should come up with whatever worked best in their areas.

Ninety Afghan civilians were killed by American and NATO troops during the first four months of the year — almost two and a half times the number during the same period last year — while 100 others were wounded. The deadliest episode occurred in February when 27 civilians who were mistaken for Taliban fighters were killed by American attack helicopters.

That has abruptly reversed the downward trend that, according to United Nations researchers, began last year after Gen. Stanley A. McChrystal, the overall commander of American and NATO forces, put in place measures to reduce civilian casualties.

Some of the increase can be explained by heightened military operations, but the rise in civilian deaths this year has outpaced the increase in the number of Western troops.

The shootings inflame Afghans, who see them as proof that Western forces operate with impunity. President Hamid Karzai has been harshly critical of civilian deaths caused by the American military, saying they jeopardize any progress that the military offensive might be making.

Even in thanking American troops during a trip to Bagram Air Base on Saturday, Mr. Karzai again called for caution in their operations, although more obliquely. “When you’re out in the fields in Afghanistan alongside Afghan soldiers, it is like any other society,” The Associated Press reported Mr. Karzai as saying. “There are families. There are children. There are women. There are elderly people. There are young people and people who are ill. I’m sure that you take appropriate and good care of the situation when you face it.”