Quick summary: No more engaging insurgents near homes unless absolutely necessary.

Gen. Stanley McChrystal, who took command of international forces in Afghanistan this month, has said his measure of effectiveness will be the "number of Afghans shielded from violence" — not the number of militants killed.

McChrystal will issue orders within days saying troops may attack insurgents hiding in Afghan houses if U.S. or NATO forces are in imminent danger, said U.S. military spokesman Rear Adm. Greg Smith.

"But if there is a compound they're taking fire from and they can remove themselves from the area safely, without any undue danger to the forces, then that's the option they should take," Smith said. "Because in these compounds we know there are often civilians kept captive by the Taliban."