A Nato service member has died in a roadside bombing in southern Afghanistan.
The bomb killed four civilians and wounded one other in the Uruzgan province, some 250 miles south-west of Kabul, officials said.
Meanwhile, allied and Afghan forces killed three senior Taliban figures in Farah province and captured 11 fighters and sympathisers.
The continuing bloodshed comes despite tentative efforts by the Obama administration and other governments to establish a peace process with the Taliban to help end the 10-year war.
A senior US administration official said Washington plans to continue a series of secret meetings with Taliban representatives in Europe and the Persian Gulf region next year.
President Hamid Karzai said this week that his government would accept the Taliban opening a liaison office in Turkey, the Gulf state of Qatar or Saudi Arabia for the purpose of holding peace talks.
This latest death brings the December toll for Nato troops killed in Afghanistan to 26, while the year's toll so far is 542. The yearly total is considerably lower than for 2010, when more than 700 troops died.