NATO and Afghan troops called in airstrikes during a battle against insurgents that left 20 suspected militants but also several civilians dead, officials said Tuesday.

The casualty figures varied widely. Afghan officials said between three and 12 civilians were killed in the fighting Monday in a remote area of Wardak province, just west of the capital, Kabul.

NATO's force in Afghanistan said 50 insurgents were trying to set up an ambush and that fighter aircraft dropped two bombs on their position.

Spokesman Maj. Charles Anthony said soldiers were investigating the incident to see if civilians had perished.

"We've been looking since yesterday," Anthony said. "We still have not gotten any evidence of any civilian casualties. I'm not saying it's not possible."

NATO said it killed "numerous" enemy fighters.

Mohammad Hussein Fahami, the deputy head of the Wardak provincial council, said 12 civilians were killed — eight people from one family and four others. Ten civilians were wounded, he said.

Anthony said soldiers had been on the ground to guide the bombs to their targets. He said ISAF has "no evidence" the bombs hit a housing compound.

Some 700 civilians have died in fighting this year, according to an Associated Press count based on figures from Afghan and Western officials. About half of those deaths were caused by U.S. and NATO forces.

Maj. Zalmay Khan, an Afghan army commander, said 20 enemy fighters died in the joint NATO-Afghan operation. But a governor's aide, Mohammad Sadiq, said the operation killed 12 fighters and three civilians.

Khan said militants were firing at Afghan and NATO forces from the cover of civilian homes.

Casualty figures from remote battles often vary widely in Afghanistan and are hard to independently verify. U.S. and NATO officials say insurgents commonly force villagers to claim civilians casualties when none happened and that sometimes villagers falsely claim deaths in order to receive monetary compensation.

President Hamid Karzai has repeatedly pleaded with international forces to avoid civilian deaths and injuries.

Separately, the U.S.-led coalition said one child and five militants were killed in Zabul province Tuesday after militants fired on coalition soldiers from a tent.

Afghanistan this year has seen the heaviest fighting since the 2001 ouster of the Taliban. In all, more than 5,200 people have died in insurgency related violence, according to the AP count.