A US military helicopter crashed on Tuesday near the North Korean border, a South Korean defence official said, with no reported casualties.
The helicopter, identified by the Yonhap news agency as a UH-60 Black Hawk, came down in Cheolwon county, which touches on the border with North Korea, a defence ministry spokesman said.
The precise cause of the crash was not immediately clear, but the incident occurred during ongoing South Korea-US joint military exercises.
Yonhap quoted emergency rescue workers as saying the 12 service personnel on board the helicopter had survived the crash, which comes at a time of heightened military tensions on the Korean peninsula.
North Korea has condemned the joint exercises as a rehearsal for invasion, and made a series of dire threats of military retaliation.
There are 28,500 US military personnel permanently stationed in South Korea.