A US Marine helicopter taking part in a joint military exercise with South Korea crashed near the North Korean border on Tuesday, with no reported casualties.
According to a military statement, the US Marine CH-53E "Super Stallion" helicopter was "conducting routine flight operations" during an exercise near South Korea's Jipo-ri Range when it made a "hard landing" near the North's border.
All 21 people on board were hospitalized, NBC News reported. 15 were treated and released, while six remained in stable condition.
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The crew of the helicopter is stationed in Okinawa, according to CBS, which added that those on board were taken to the hospital.
28,500 US military personnel are currently stationed in South Korea, and those troops have recently been carrying out joint exercises, which have drawn the ire of the increasingly aggressive North.
Monday saw North Korea celebrate the 101st birthday of founding father Kim Il Sung, a holiday widely known as the "day of the sun."
The North did not carry out a test of the long-range Musudan missile as had been previously threatened, although it did issue new military threats.
North Korea's state KCNA news agency claimed that "Our retaliatory action will start without any notice from now," and that such actions would "start immediately," Reuters reported, a statement apparently aimed at South Korea.