The missing US Marine Corps helicopter involved in disaster relief efforts in Nepal may have gone down in a river in the Charikot area hit hard by an earthquake.

The Marine Corps UH-1Y Huey helicopter participating in earthquake relief operations lost radio contact on Tuesday after its crew was heard talking about fuel problems.

"The info we have is that it is down in one of the rivers, but none of the choppers has seen it yet," Major Rajan Dahal, second-in-command of the Barda Bahadur Batallion, said.

"There are 400-plus of our ground troops looking for it also, by this evening, we might get it."

Army Major Dave Eastburn, a spokesman for US Pacific Command, said six US Marines and two Nepalese soldiers were aboard the helicopter.

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The helicopter was one of three Marine Corps helicopters participating in relief operations in Charikot, one of the villages hardest hit by a magnitude-7.3 earthquake on Tuesday.

The quake was the worst aftershock following the magnitude-7.8 earthquake that hit Nepal last month, which left more than 8,000 people dead and destroyed parts of the country.

Tuesday's powerful quake killed at least 48 people and injured more than 1,100 in Nepal, police spokesman Kamal Singh Bam said.

Seventeen people were killed in the Indian states of Bihar and Uttar Pradesh, the home ministry said, and Chinese media reported the death of one person in Tibet after rocks fell on a car.

The earthquake struck at a depth of 19 kilometres, 83 kilometres east of the capital Kathmandu — near the base camp for Everest — about 12:30pm local time, the United States Geological Survey said.

Reuters