A strong earthquake struck central Myanmar on Friday, and people rushed out of buildings in panic in Yangon and also in Bangkok, the capital of neighbouring Thailand, witnesses said.

The United States Geological Survey (USGS) said the quake was of 7.7 magnitude and at a depth of 10 km (6.2 miles). It was followed by a powerful aftershock.

The epicentre was about 17.2 km from the city of Mandalay, which has a population of about 1.2 million, according to USGS.

There was no immediate word from Myanmar on damage.

An officer from the Myanmar Fire Services Department told Reuters: "We have started the search and going around Yangon to check for casualties and damage. So far, we have no information yet."

Social media posts from Mandalay showed collapsed buildings and debris strewn across streets. Reuters could not immediately verify the posts.

Witnesses contacted in Yangon said many people ran out from buildings in the city, the largest in the country.

Witnesses in Bangkok said people ran out onto the streets in panic, many of them hotel guests in bathrobes and swimming costumes.