KABUL, Afghanistan -- The commander of NATO and U.S. forces in Afghanistan issued updated rules of battle Wednesday, repeating his predecessor's curbs on use of air power and heavy weapons when civilians are at risk, but stressing the right of troops to defend themselves.

The new guidance comes after widespread complaints from troops that rules laid down by the former commander, Gen. Stanley McChrystal, were putting them in danger and handing the advantage to the Taliban.

There had been speculation that Gen. David Petraeus, who took over from McChrystal a month ago, might ease the rules. But Petraeus, like McChrystal, emphasized that protecting the Afghan people was the top priority in the war.

"We must continue -- indeed, redouble -- our efforts to reduce the loss of innocent civilian life to an absolute minimum," Petraeus wrote in the document released by the NATO command Wednesday. Some sections were not released for security reasons, the command said.

McChrystal stressed the need to reduce civilian casualties as a tool for winning the war, noting that every civilian killed by crossfire created a legion of family members with a grudge against NATO forces and motivation to join the Taliban.

Under this guidance, NATO forces drastically restricted the use of airstrikes, which previously had been called in without knowledge of who was inside a building. Troops also were instructed to fire only on people who were actively firing on them.

Though McChrystal's directive frustrated many soldiers in the field, it also led to a drop in civilian deaths attributed to NATO forces.

Petraeus said nothing in the guidance was meant to hinder the right to self-defense.

"We must employ all assets to ensure our troopers' safety, keeping in mind the importance of protecting the Afghan people as we do," Petraeus wrote.

A spokesman for NATO forces said the directive will help troops understand how to balance the two.

"We also have now an absolutely clear wording and language on the necessary balance between the right of self-defense, the protection of the people, and the assurance of moms and dads back home that their boys and girls absolutely do have the necessary means and measures to achieve mission and success," NATO spokesman Josef Blotz said.

The new directive implied that some lower-level commanders had misinterpreted McChrystal's guidance and made rules in their areas more restrictive than needed.