Taliban insurgents killed six troops from Nato-led forces and three Afghan soldiers in an ambush in eastern Afghanistan today.
It was the heaviest loss suffered by International Security Assistance Force (ISAF) troops in Afghanistan in three months.
It as Afghan and international troops are engaged in daily battles throughout the country across trying to contain the spreading Taliban insurgency.
Eight ISAF troops and 11 Afghan soldiers were also wounded in fighting which began when insurgents ambushed their patrol using rocket-propelled grenades as the troops were returning from a meeting with local elders.
Most ISAF troops based in the east of the country are American, but the force is withholding confirmation of the nationalities of the dead soldiers pending notification of next of kin.
Elsewhere, a suicide bomber killed one civilian and wounded three other people in the northern province of Kunduz today.
In the west of the country, Afghan troops backed by ISAF soldiers retook the district of Gulistan, captured by the Taliban nearly two weeks ago, the Afghan Defence Ministry said.
Some 20 Taliban, including a commander, were killed or wounded and another 20 detained in the clashes.
Foreign fighters were helping the Taliban, the regional police Farah police chief Abdul Rahman Sarjang said.
"We have credible intelligence that Iranians and Pakistanis are fighting alongside the Taliban insurgents.
"We have also captured a large amount of brand new Iranian-made ammunition recently smuggled to Afghanistan," he said.