A massive earthquake has hit Nepal and north India, collapsing a nine-storey tower in Kathmandu and killing about a dozen people, witnesses say.

About a dozen bodies were taken away from the ruins of the historic Dharahara tower in the centre of the capital, which sustained massive damage when the magnitude-7.9 quake struck at lunchtime (local time), according to an AFP photographer at the scene.

Authorities earlier said a 15-year-old girl in northern India was killed when the earthquake brought down the wall of her home.

Another girl was killed by a falling statue in a town outside Nepal's capital Kathmandu, according to Nepal's state radio.

The Dharahara tower was a historic landmark that had been open to visitors for the last 10 years and had a viewing balcony on its eighth floor.

Kanak Masni, a journalist in Kathmandu, told CNN by phone that a historic building in Kathmandu called Dharahara -- also known as Bhimsen Tower -- was down. The building, nearly 63 meters tall, provided visitors with a panoramic view of of the Kathmandu valley. It was built in 1832.

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.

The quake was 31 kilometres deep.

Strong tremors were felt as far away as New Delhi and other northern cities in India.

"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 officer said.


Agencies/QH