The hunt for a Marine helicopter that vanished in Nepal was expanded Wednesday with four U.S. aircraft and hundreds of Nepalese troops joining the search.
However, there was no sign of the missing UH-1Y Huey which was carrying six Marines and two Nepalese service members.
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' Alexander Smith and Reuters contributed to this report.