An earthquake measuring 6.6 on the Richter scale jolted Tibet on Thursday, authorities said, adding that there were no reports of casualties.

The quake struck Nyima County at 4.07 a.m., Xinhua news agency quoted the China Earthquake Networks Center as saying.

The epicenter was monitored at 33.19 degrees north latitude and 86.81 degrees east longitude, with a depth of 10 km.

The county has launched an emergency response.

Telecommunication, electricity and water supply remain normal in the county.

The epicenter was less than 20 km away from Rongmar Township where the quake was strongly felt.

Rongmar, at an average altitude of over 5,000 metres, administers two villages.