SATTAHIP, Thailand (AP) — Troops from South Korea joined their Thai and U.S counterparts on Saturday in an amphibious vehicle landing drill as part of Southeast Asia's largest multinational military exercise.

The 300 soldiers from South Korea who joined 2,000 U.S. Marines and Thai soldiers in eastern Thailand marked the highest numbers participating from the East Asian country since it joined the Cobra Gold exercise in 2010, and comes at a time when tensions are particularly high on the Korean Peninsula.

Tensions in the Koreas primarily involve concerns over North Korea's nuclear capability, which has led to saber-rattling declarations in Washington and Pyongyang.

"Our friends in the Republic of Korea, South Koreans, we stand by them. We work with them," said Gen. Robert Neller, commandant of the U.S. Marine Corps. "We are allies. We continue to coordinate and keep pressure on. Hopefully through diplomatic means we would be able to come to some successful resolution of the problem."

Some 11,075 service members from 29 countries are taking part in this year's exercise, with Thailand, the U.S., Singapore, Japan, South Korea, Indonesia and Malaysia the seven main participants. There are 6,800 U.S. troops attending the exercise.

Ships taking part in Saturday's exercise included the U.S. amphibious assault ship USS Bonhomme Richard and the South Korean landing ship Cheon Ja Bong.

The weeklong exercise, centered around the Sattahip Royal Thai Marine Corps Base in the eastern province of Chonburi, includes humanitarian components such as evacuation drills, as well as traditional military exercises such as the amphibious landing.

The aims of the exercise are to enhance security cooperation, develop peacekeeping forces and maintain readiness for humanitarian aid and disaster relief missions.