The quake struck Dingri county with a magnitude of 6.8 near the border with Nepal at 9:05 am (0105 GMT), according to the China Earthquake Networks Center (CENC). The US Geological Survey reported the quake as magnitude 7.1.

"Dingri county and its surrounding areas experienced very strong tremors, and many buildings near the epicentre have collapsed," state broadcaster CCTV said.

"The reporter learned that nine people have been confirmed dead so far," adding that as of 10 am, "multiple aftershocks" had been recorded, the largest measuring 4.4 in magnitude.

Xinhua news agency said that "local authorities are reaching out to various townships in the county to assess the impact of the quake".

The high-altitude county in the Tibet region is home to around 62,000 people and situated on the Chinese side of Mount Everest.

While earthquakes are common in the region, Tuesday's quake was the most powerful recorded within a 200-kilometre radius in the last five years, the CENC added.

As well as Kathmandu, areas around Lobuche in Nepal in the high mountains near Everest were also rattled by the tremor and aftershocks.

"It shook quite strongly here, everyone is awake, but we don't know about any damages yet," said government official Jagat Prasad Bhusal in Nepal's Namche region, which lies nearer to Everest.

Nepal lies on a major geological faultline where the Indian tectonic plate pushes up into the Eurasian plate, forming the Himalayas, and earthquakes are a regular occurrence.

In 2015, nearly 9,000 people died and more than 22,000 were injured when a 7.8-magnitude quake struck Nepal, destroying more than half a million homes.