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A U.S. Marine helicopter supporting earthquake relief in Nepal was declared missing Tuesday with eight people on board, a military spokesman said.

The UH-1Y Huey with two Nepalese soldiers and six U.S. Marines on board disappeared over Charikot, Nepal, at about 10 p.m. local time (12:15 p.m. ET), said U.S. Pacific Command spokesman Army Maj. Dave Eastburn.

Pentagon spokesman Col. Steve Warren said the U.S. military is hopeful that the missing helicopter landed and is out of communication. A military official told NBC News there is "no indication that there was a crash" but "it is dark," so they could not immediately confirm that.

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A U.S. defense official told NBC News that the Marines were equipped with a GPS device, a radio and an emergency beacon, but the helicopter was flying over difficult terrain, which might render the equipment ineffective. The official said the Marines also had a satellite phone, strobes, flares and signal mirrors.

Eastburn said military personnel in Nepal were “responding to the emergency” and the incident was under investigation. Nepalese military forces on the ground near the last known location of the aircraft were also assisting in the search, according to a statement from U.S. Pacific Command.

U.S. and Nepalese-supported aerial searches will start at daybreak, the statement, released just after midnight Nepal time, said.

The helicopter is part of Marine Light Attack Helicopter Squadron 469, which is part of the 3rd Marine Air Wing based at Camp Pendleton in California, according to NBC San Diego.

Charikot was one of the villages hardest hit by a 7.3-magnitude quake on Tuesday.

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4 VTOL Ospreys & 1 Hueys now on-the-ground to help carry relief for #NepalQuake villages. More to come! @USAID pic.twitter.com/r6Be4tov23 — USAID Nepal (@USAIDNepal) May 3, 2015

— Elisha Fieldstadt and Courtney Kube