Four US servicemen with the Nato-led force were killed by a roadside bomb in southern Afghanistan today.
The latest deaths make 2009 the deadliest year for foreign troops since the overthrow of the Taliban in 2001.
The deaths bring the number of foreign forces killed in 2009 to 295, according to website icasualties.org, which compiles official data. The previous deadliest year was 2008 when 294 foreign troops died.
Another roadside bomb killed four Afghan civilians working for a construction company in Yousef Khil district, Paktika province.
Elsewhere, Afghan troops arrested a key Taliban bomb maker and found a cache of 300 improvised explosive devices in Logar province to the south of Kabul, the defence ministry said.
The latest deaths highlight the steadily worsening violence in the country, which has been in political limbo since a disputed presidential election last week.
Afghan election authorities were preparing later today to publish the first partial results from the presidential election, but the tiny sample may do little to resolve a growing war of words on the outcome.
The election has also been a test of President Barack Obama's strategy of rushing thousands of extra US troops to the country this year in a bid to reverse Taliban gains.
More than 30,000 extra US troops arrived in Afghanistan this year, most part of a package of reinforcements ordered by Mr Obama in May. There are now more than 100,000 Western troops in the country, 63,000 of them Americans.
The US reinforcements sent by Mr Obama, along with a British contingent already deployed in the south of the country, have advanced deep into formerly Taliban-held territory, taking heavy casualties mainly from roadside bombs. More Western troops have died since March than in the entire period from 2001-2004.
There are fears that a delay in resolving the dispute over the Afghan election could stoke further instability.
Late yesterday Finance Minister Hazrat Omar Zakhilwal said figures supplied to him as a member of the cabinet showed president Hamid Karzai leading with 68 per cent of the vote and avoiding a second round.
A spokesman for Mr Karzai's main rival, Abdullah Abdullah, said those figures were false, however. Mr Abdullah has also claimed to be in the lead, and alleges massive fraud on Karzai's behalf.
Reuters