Three soldiers from a U.S.-led coalition force in Afghanistan have been killed in a blast in the south of the country, the U.S. military said on Tuesday. Violence has surged in Afghanistan this year with about 3,000 people, at least 1,000 of them civilians, killed in the bloodiest year since U.S.-led and Afghan forces overthrew the Taliban in 2001, Reuters reported. This summer has also been the deadliest period for foreign troops in the country, with the militants launching more daring and deadly attacks. "Three coalition service members were killed Sept. 29 in southern Afghanistan when their vehicle struck an IED," the U.S. military said in a statement, referring to an improvised explosive device, or roadside bomb.