Four U.S. servicemen were killed by a roadside bomb in Afghanistan on Tuesday, making 2009 the deadliest year for the growing contingent of foreign troops since the overthrow of the Taliban in 2001.
The deaths highlighted the steadily worsening violence in the country, which has been in political limbo since a disputed presidential election last week.
The election has also been a test of President Barack Obama's strategy of rushing thousands of extra U.S. troops to the country this year in a bid to reverse Taliban gains.
More than 30,000 extra U.S. troops arrived in Afghanistan this year, most part of a package of reinforcements ordered by Obama in May. There are now more than 100,000 Western troops in the country, 63,000 of them Americans.
A NATO statement said the four U.S. service members were killed in the south, the Taliban's heartland, but gave no further details.
That would bring the number of foreign troops who died in Afghanistan this year to 295, according to Web site icasualties.org, which compiles figures. Last year was the previous deadliest year when 294 were killed.
However, a count by The Associated Press puts the number of overall NATO deaths this year at 292. Last year, 286 died, according to AP figures.
The U.S. reinforcements sent by 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 election could stoke further instability.
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