POSTED: Tuesday, April 16, 2013 - 8:04am
UPDATED: Tuesday, April 16, 2013 - 8:06am
SEOUL, South Korea (CNN) — SEOUL, South Korea (CNN) -- A U.S. Marine helicopter participating in annual military exercises in South Korea made a hard landing Tuesday in a province that borders North Korea, the U.S. military said. The 21 personnel on board the CH-53E Super Stallion helicopter, which was making routine flights as part of the exercises, were taken to a hospital at the United States' Yongsan Garrison in South Korea, the military said in a statement. Fifteen of those have since been released from the hospital, and the other six are in stable condition, the statement said.