As of this morning, after more than 12 hours of extensive search efforts U.S. military and Nepalese rescue teams have found no sign of the missing Marine corps Huey helicopter with six Marines and two Nepalese soldiers on board.
The search, which included U.S. military helicopters and tilt-rotor Opsrey aircraft along with Nepalese ground forces, found no trace of the helicopter, which went down in the rugged mountainous area near the village of Charikot nearly 24 hours ago.
U.S. military and defense officials had hoped the helicopter safely landed and the crew was unable to communicate because of the mountainous terrain. But after today's search efforts camp up empty that optimism has faded. According to one senior military official, "This does not bode well."
The helicopter disappeared on Tuesday night while delivering aid to one of the hardest-hit regions suffering from last month's devastating magnitude-7.8 earthquake that killed more than 8,000 people. The crew reportedly radioed to say the chopper was having fuel problems before suddenly disappearing.
Hours earlier, a powerful aftershock rocked Nepal and killed dozens more people.
At around 9:45 a.m. local time on Wednesday (midnight ET), two Marine MV-22B Osprey tiltrotor aircraft were launched from Kathmandu in search of the missing Huey, according to a statement from Joint Task Force 505 that is assisting with the Nepal relief effort.
These followed two UH-1Y Hueys that were launched around three hours earlier, the statement said. The two pairs of aircraft were with the Marine Medium Tiltrotor Squadron 262 and the Marine Light Attack Helicopter Squadron 469 respectively.
Army Col. Steve Warren, a spokesman for the Pentagon, said late Tuesday that the U.S. was hopeful the missing helicopter landed and merely was out of communication range. A military official told NBC News there is "no indication that there was a crash" but that the conclusion couldn't immediately be confirmed.
The Marines on board were equipped with a GPS device, a radio and an emergency beacon but that the helicopter was flying over difficult terrain, which might render the equipment ineffective, a U.S. defense official told NBC News on Tuesday.
The helicopter had been delivering aid in the Dolakha district, one of the hardest hit by the April 25 quake, and stopped responding near the village of Charikot. The DoD said the aircraft did not issue a distress call.
Major Rajan Dahal, second-in-command of Nepal's Barda Bahadur Battalion, told Reuters that more than 400 ground troops were also involved in the search.
However, one Nepal Home Ministry official told the news agency that she feared the search was diverting resources from relief and rescue work.
"The work of sending relief and rescuing the injured people to hospitals has been delayed due to this," Laxmi Prasad Dhal told Reuters.
NBC News' Courtney Kube and The Associated Press contributed to this article, which originally appeared on NBCNews.com.