An earthquake measuring 7.9 magnitude, and only 2 km deep, struck east of Pokhara in Nepal on Saturday causing buildings in the capital Kathmandu to collapse, injuring many and leaving a pall of dust over the city, witnesses said.
At least two people were killed.
At the main hospital in Kathmandu, people with broken limbs and arms were being rushed in for treatment. It was unclear how many people have been injured.
A girl died after a statue fell on her in a park in Kathmandu, a witness said, while another died in India when her house collapsed.
A Reuters reporter in Kathmandu said he had seen some buildings collapse and walls of several houses reduced to rubble. “Everyone is out in the streets, people are rushing to the hospital,” the reporter said.
Photographs posted online showed buildings left in rubble, large cracks along roads and worried residents sitting in the street holding babies.
Tremors were felt as far away as New Delhi and other northern cities in India, with reports of tremors lasting almost one minute.
"Massive tremors have been felt here in Delhi and several other parts of India," said a newsreader on NDTV in Delhi.
"You can see pictures of our Delhi studios, where the windows rattled and everything shook for a very long time, for a minute perhaps or longer," she said as footage showed studio ceiling camera lights shaking.
A police officer in the control room of neighbouring Indian state of Bihar said the phone lines were jammed with callers from across the heavily populated state. "We don't know about the casualties, we are flooded with calls."
The US Geological Survey said the quake, initially measured at 7.7 but upgraded to 7.9 magnitude, struck 80 km (50 miles) east of Pokhara.
"We are in the process of finding more information and are working to reach out to those affected, both at home & in Nepal," tweeted Indian Prime Minister Narendra Modi.
Nepal’s lack of disaster preparedness, the decrepit buildings packed cheek by jowl along the tiny lanes and the large families who live in these homes make the prospect of a major earthquake a serious concern.