FORT DRUM, N.Y. -- Elements from the 2nd Brigade Combat Team, 10th Mountain Division (LI), will deploy to southern Afghanistan in support of Resolute Support Mission during the spring and summer.The roughly 1,660 Soldiers will serve as advisers to the Afghan National Security Forces, protecting U.S. forces on bases or work on the Train Advise Assist Command -- South staff. The deployment is expected to last nine months."We are going to focus on helping the Afghan National Security Forces refine their plan so their capabilities outlast our presence, said Col. David S. Doyle, 2nd Brigade Combat Team commander. "Our team, including both our Soldiers and Families, is the right organization to take on this mission."The brigade's last deployment ended in October 2013. This will be the brigade's fourth deployment to Afghanistan.The brigade recently completed a monthlong training exercise at the Joint Readiness Training Center, Fort Polk, La.