US Pacific Command spokesman Major Dave Eastburn told reporters the disappearance of the UH-1Y Huey helicopter occurred at about 10 p.m. local time near Charikot, Nepal while the helicopter was involved in providing earthquake relief.
Six US Marines and two Nepalese soldiers were on board.
Charikot was one of the villages severely hit by another major quake on Tuesday, about three weeks after a deadly quake killed more than 8,000 people and injured 17,000 more.
"A 6.8-magnitude earthquake has hit Nepal at 12:54 and the epicenter is in Dolakha, some 130 kilometers from Kathmandu," Nepalese Home Ministry said in a statement. The US Geological Survey had recorded the magnitude of Tuesdays quake as 7.3.(*)