A Black Hawk helicopter sent to retrieve the bodies of five victims of a weekend helicopter crash went missing Tuesday near the Thai-Myanmar border, military sources confirmed, according to dpa. Army headquarters in Bangkok lost contact with the chopper midday after it entered the mountainous Kaeng Krachan National Park area, 165 kilometres south-west of Bangkok. "We've lost contact with them for over an hour," army spokesman Colonel Sansern Keowkamnerd said. "We still can't confirm the helicopter has crashed," he added. There were at least nine people on board the aircraft, the highest ranking of whom was Major General Thawan Reungsri. It was on a mission to retrieve the bodies of five army officers who were killed Saturday when their military helicopter crashed in Kaeng Krachan.