U.S. Defense Secretary Robert Gates has ordered the deployment of a combat aviation brigade to Afghanistan next year as part of a buildup of forces to counter rising insurgent violence, a U.S. military official said Friday. The official told reporters on condition of anonymity that Gates has signed the order in response to a request for more forces by General David McKiernan, the U.S. commander in Afghanistan. “This is the beginning of the sourcing of the increased requirement that [McKiernan] has asked for,” the official said, adding that the Army brigade of about 2,800 soldiers, equipped with both attack and transport helicopters, would deploy to Afghanistan after January. McKiernan has requested more than 20,000 additional U.S. soldiers to counter a rise in insurgent violence, particularly in eastern and southern Afghanistan. He has asked for four combat brigades and the aviation brigade—which together number about 14,000 troops—and other support forces. One of the ground combat brigades is scheduled to deploy in January, and Gates—who will continue as Pentagon chief under President-elect Barack Obama—said last week he expected to provide two more brigades by late spring. The buildup would nearly double the U.S. military presence in Afghanistan, raising it from 31,000 soldiers to over 50,000.