Six NATO-led soldiers and three Afghan troops were killed in heavy fighting in eastern Afghanistan, NATO's International Security Assistance Force announced.
Another eight ISAF soldiers and 11 Afghan troops were wounded in the battle on Friday which erupted after the forces were ambushed, ISAF said in a statement.
This is one of the bloodiest incident, involving ISAF troops and is believed to take this year's death toll among foreign soldiers up to 200.
The soldiers were on a foot patrol when they were attacked from several positions by insurgents armed with guns and rocket-propelled grenades, ISAF said.
"The combined force repelled the insurgent attack with small-arms, machine guns, mortars, artillery, and close-air support," it said. The remains of one insurgent were discovered afterwards.
The 37-nation ISAF does not release the nationalities of its casualties.
There are currently more than 50,000 foreign soldiers in Afghanistan.
About 40,000 are under the command of ISAF, the rest form a coalition under US direction.