KATHMANDU - A new earthquake and powerful aftershocks killed dozens of people and brought fresh terror to a traumatised Nepal on Tuesday as buildings already damaged in a monster quake last month came tumbling down.

Weeks after the country's deadliest quake in more than 80 years, terrified residents once again fled onto the streets as houses collapsed and landslides blocked roads, hampering the relief effort.

Authorities in Nepal said at least 48 people were killed and more than 1,100 injured, while 17 people also died across the border in northern India.

The 7.3-magnitude quake struck at 12:35 pm, some 76 kilometres (47 miles) east of Kathmandu, the US Geological Survey said, after a 7.8-magnitude quake on April 25 killed more than 8,000 people.

Tuesday's quake was felt as far away as New Delhi, and caused buildings to collapse in Tibet in neighbouring China, killing at least one person there. A second tremor of 6.3-magnitude struck Nepal around half an hour later, followed by yet more aftershocks, according to the USGS.

Eight people died in Kathmandu Valley and two major buildings collapsed in the capital. But Dolakha and Sindhupalchowk, two of districts worst affected by the original quake, bore the brunt of the damage. In Dolakha alone, 26 people were confirmed dead.

"Many houses have collapsed in Dolakha... there is a chance that the number of dead from the district will go up," said Home Minister Bam Dev Gautam.

The Red Cross said it had received reports of large-scale casualties in the town of Chautara in Sindhupalchowk, where its Norwegian branch is running a field hospital. "Hundreds of people are pouring in. They are treating dozens for injuries and they have performed more than a dozen surgeries," said spokeswoman Nichola Jones. An emergency tent hospital in Tatopani near the Chinese border run by the Canadian Red Cross had been damaged by a landslide, she said.

There have been several reports of landslides in the worst-hit areas, making the task of getting relief to remote communities in the mountainous country even more difficult. Save the Children said the Gorkha region, near the epicentre of the April 25 quake, had also been hit by landslides and many key roads were blocked.

The charity said two major buildings had collapsed in Kathmandu, while many more multi-storey buildings were showing large fissures.

Nepalese television showed the parliament building swaying, forcing lawmakers to flee.

Regine Kopplow, a German aid worker who was in the Dolakha district headquarters of Charikot when the latest quake hit, saw huge dust clouds rise into the air as buildings collapsed.  "I saw a woman in the building opposite jump from the third floor who suffered injuries to her leg, elbow and hand," said Kopplow, who works for Concern Worldwide. "People stayed outside, the shaking continued. Some people were crying, hugging each other and sitting on the ground supporting each other."

US helicopter missing in Nepal with 8 aboard

A US Marine Corps helicopter carrying out earthquake relief in Nepal was reported missing on Tuesday with eight personnel on board, officials said.

‘The incident occurred near Charikot, Nepal while the aircraft was conducting humanitarian assistance and disaster relief operations,’ said Major Dave Eastburn, spokesman for US Pacific Command. The UH-1Y Huey, which was carrying tarps and rice, had just dropped off supplies and was headed to another destination, officials said.

Before the chopper went missing, there was ‘some chatter about a fuel problem’ on the radio from the helicopter crew, Pentagon spokesman Colonel Steven Warren said. The chopper was carrying six US Marines and two soldiers from the Nepalese army, officials said. The Huey helicopter was last seen west of Charikot but a search of the area was unsuccessful.

A search by aircraft before nightfall had not spotted any sign of smoke or any crash site, raising hopes the helicopter may have made a safe emergency landing, he said. The Nepalese army was conducting a search on the ground but aircraft could not fly until daylight to resume the search from the air. Warren said that ‘no emergency beacon has been detected at this time’ from the helicopter crew.

 Due to the rugged, mountainous terrain, even if a beacon signal was switched on it might not be picked up easily as it requires a clear line of sight, he added.

About 300 US military troops have deployed to support the relief effort in Nepal, where aftershocks continue to claim lives after last month's massive quake. A new earthquake and powerful aftershocks killed dozens of people and brought fresh terror to Nepal on Tuesday. The helicopter was among more than a dozen US military aircraft devoted to aid operations, including two other Huey choppers and four tilt-rotor Ospreys as well as cargo planes. Relief teams from around the world are still working to provide water, food and medical assistance to Nepalis after the April 25 quake - the country's deadliest in more than 80 years.