Guwahati/Thimpu, Sep 21 - A high magnitude earthquake measuring 6.3 on the Richter scale Monday killed at least 10 people in the Himalayan kingdom of Bhutan and left dozens more injured, while several buildings developed cracks in India's northeastern state of Assam.

Bhutan Broadcasting Service (BSS), the national broadcaster, quoted Bhutanese government officials and witnesses as confirming 10 deaths.

'Of the 10 deaths, three were of Indian origin who were engaged in road widening work. They died after being hit by falling boulders,' the BSS report said.

The bodies of the three Indians killed, all from Assam, were handed over to their relatives in the border town of Darranga in Assam late Monday.

'Five people were killed in Mongar and two deaths were reported from Trashigang in eastern Bhutan,' U. Tenzing, the director of Bhutan's disaster management department, said, adding, 'We are trying to get more information from the affected places.'

The casualties were reported when their houses collapsed or some of them were hit by falling debris.

'Most of the mud and stone houses with tin roofs caved in with several schools, monasteries and houses damaged in the earthquake,' another senior Bhutanese police official said requesting not to be named.

Police and civil rescue teams have since fanned out to the quake hit eastern districts of Mongar and Trashigang to look for people who could be trapped or injured.

'There was extensive damage to monasteries, schools, houses and other structures in eastern Bhutan,' D. Dhendup, a Bhutanese official, said.

Meanwhile, Bhutan's Home Minister Lyonpo Minjur Dorji urged people not to panic.