At least 128 people were killed and dozens injured in Nepal when a strong earthquake struck the western area of Jajarkot, officials said on Saturday, as houses in the area collapsed and buildings as far as New Delhi in neighbouring India shook.

The quake occurred at 11:47 pm (1802 GMT) on Friday with a magnitude 6.4, Nepal's National Seismological Centre said. The German Research Centre for Geosciences measured the quake at 5.7, downgrading it from 6.2, while the US Geological Survey pegged it at 5.6.

The quake is the deadliest since 2015 when about 9,000 people were killed in two earthquakes in the Himalayan country. Whole towns, centuries-old temples and other historic sites were reduced to rubble then, with more than a million houses destroyed, at a cost to the economy of $6 billion.

Officials feared the death toll in Friday's quake could rise as they had not been able to establish contact in the hilly area near the epicentre, some 500 km (300 miles) west of the capital Kathmandu, where tremors were also felt. The district has a population of 190,000 with villages scattered in remote hills.

"The number of injured could be in the hundreds and the deaths could go up as well," Jajarkot district official Harish Chandra Sharma told Reuters by phone.

Police spokesman Kuber Kadayat said 92 people were killed in Jajarkot and 36 in neighbouring Rukum West district, both in Karnali province. The epicentre was in the village of Ramidanda.

At least 85 people were injured in Rukum West and 55 in Jajarkot, an official in the prime minister's office said, while Sharma said at least 50 people were in hospitals in Jajarkot alone.

"Many houses have collapsed, many others have developed cracks. Thousands of residents spent the entire night in cold, open grounds because they were too scared to go in into the cracked houses as aftershocks struck," Sharma said. "I have myself not been able to go in."

Search and rescue must clear roads blocked by landslides, triggered by the earthquake, to reach the affected areas, police officer Namaraj Bhattarai said.

Prime Minister Pushpa Kamal Dahal flew to the area early on Saturday with a 16-member army medical team to oversee search, rescue and relief, his office said.

Dahal, posting on the X social media platform, expressed deep sorrow at the loss of life and property in the quake and ordered security agencies to launch immediate rescue and relief operations.

Local media footage showed crumbled facades of multi-storied brick houses, with large pieces of furniture scattered. Videos on X showed people running into the street as some buildings were evacuated.

"Houses have collapsed. People rushed out of their homes. I am out in the crowd of terrified residents. We are trying to find details of damage," police official Santosh Rokka said by phone.