The midday temblor with an epicenter near Mandalay, Myanmar's second largest city, was followed by a strong 6.4 magnitude aftershock.
Myanmar's military-run government declared a state of emergency in six regions and states including the capital Naypyitaw and Mandalay, but with the country in the midst of a prolonged bloody civil war it was not clear how help would get to many regions.
The Red Cross said downed power lines are adding to challenges for their teams trying to reach Mandalay and Sagaing regions and southern Shan state.
“Initial reports from the ground suggest the earthquake has caused significant damage,” the Red Cross said. “Information on humanitarian needs is still being gathered.”
In Bangkok, a construction worker was killed when rubble from the collapsing building site hit his truck and another was crushed by the falling debris, rescue worker Songwut Wangpon told reporters.
Defense Minister Phumtham Wechayachai said in all three people were killed at the site and 90 are missing. He offered no more details about the ongoing rescue efforts but first responders said that seven people had been rescued so far from outside the collapsed building.
Rescue workers say the rubble is still too unstable for them to try and find people possibly trapped beneath.
