KABUL, Afghanistan — Military officials today reported the year's first U.S. combat casualties in Afghanistan -- four troops killed a day earlier in the country's violent south.
In addition to the Americans killed in Sunday's blast, a British soldier died in a separate explosion, also in the south.
Roadside bombs are the No. 1 killer of Western forces in Afghanistan, and have become the signature weapon of the Taliban and other insurgents.
American troop deaths in Afghanistan surged during 2009, doubling from their levels in the previous year. Commanders have warned that the Obama administration's coming troop buildup will likely bring with it an increase in casualties, in part because the new forces will be pushing into areas of the country where the insurgents have until now held sway.
An additional 30,000 U.S. troops are to be deployed in Afghanistan this year, adding to approximately 68,000 Americans already on the ground. Separately, NATO allies are to add 7,000 troops.
The location of the latest deaths was not specified, but most Western troops in the south are based in the provinces of Helmand and Kandahar, where the Taliban movement is the strongest. Those two provinces are also a center of Afghanistan's drug trade, which has close links to the insurgency.
Most of the arriving reinforcements are to be deployed in the south, where thousands of U.S. Marines have been trying to secure a key swath of Helmand province. Other U.S. troops are working to quell a rising insurgent presence in and around Kandahar city, the Taliban's spiritual center.