Troops and emergency aircraft from the United States have arrived in Nepal to help deliver aid to remote areas hit by last week's devastating earthquake.

Relief efforts near the epicentre have been hampered by a lack of aircraft, the BBC news reported.

About 100 US marines, two helicopters and four Ospreys capable of vertical take-off are now in Kathmandu.

Their arrival comes as Nepal's only international airport has banned larger aircraft carrying aid from landing because of concerns over its runway.

More than 7,000 people died in the magnitude 7.8 earthquake. More than 14,021 people were injured.

The epicentre was in the Gorkha region, and many roads to the hilly district are impassable due to landslides.

The six aircraft are due to begin aid flights on Monday.