The resolution, which Nato labeled "a warning shot" across its own bow, came as reports emerged Wednesday of 21 villagers killed in airstrikes a toll that a Taliban spokesman said the militia would avenge.

The proposal from the upper house of parliament, which also calls for a date to be set for the withdrawal of foreign troops, suggests that Afghan support for the 5 1/2-year international military mission is crumbling amid a series of civilian deaths.

The motion reflects lawmakers' belief that negotiations with militants would be more effective than fighting, said Aminuddin Muzafari, the secretary of the upper house.

"One of the reasons I want this bill implemented is because of the civilian deaths caused by both the enemy and international forces," said Abdul Ahmad Zahidi, a parliamentarian from Ghazni province. "It's difficult to prevent civilian deaths when the Taliban go inside the homes of local people. How can you prevent casualties then? You can't."

Parliament's lower house and President Hamid Karzai must endorse the proposal for it to become law. Presidential officials were not available for comment Wednesday. However, Karzai has repeatedly said he is open to talks with Taliban.

The resolution passed Tuesday, hours before US special forces battling insurgents in Helmand province called in a series of airstrikes.

The US-led coalition said it destroyed "three enemy command and control compounds" near Sangin, a militant hotbed in the heart of Afghanistan's biggest opium poppy region that has seen heavy fighting this year.

The coalition said a "significant" number of militants died in the 16-hour battle.