U.S. Marines with the 31st Marine Expeditionary Unit provide security while Republic of Korea marines rush toward the objective during a multilateral amphibious assault exercise in Hat Yao, Thailand, on Feb. 10, 2012. The U.S. Marines were conducting the assault with Royal Thai and Republic of Korea marines during exercise Cobra Gold 2012. Cobra Gold is a regularly scheduled joint combined exercise designed to ensure regional peace and strengthen the ability of the Royal Thai Armed Forces to defend Thailand or respond to regional contingencies.