The deaths involved troops from the 12,000-member US-led coalition and not Nato's 37,000-member International Security Assistance Force. But Nato officials fear that Afghans and others don't understand the distinction.

Mounting civilian casualties have already dented support for the international mission, sparking angry demonstrations and a warning from President Hamid Karzai that Afghans can accept them no longer.

German Defence Minister Franz Josef Jung said Wednesday the recent operations by US-led troops exposed the need for restraint.

"We have to do everything to avoid that civilians are affected," Jung said on Germany's ZDF television. "We are in talks with our American friends about this."

Insurgency-related violence has spiked in 2007, with more than 1,800 people killed, according to an Associated Press count based on US, Nato and Afghan reports.

They include about 135 civilians killed by US or Nato action, a figure that also could undermine support in Western countries, especially in Europe, for the faraway deployment. About 135 civilians have also been killed by Taliban suicide bombs and attacks.

Nato's counterinsurgency strategy focuses on separating fighters from the general population and strengthening the Afghan government. The US-led coalition's counterterrorism mission involves taking out al-Qaeda or Taliban leaders and cells of skilled fighters.

While troops from the two missions communicate often and at times work together, they operate under different command structures and don't always coordinate their actions.