An earthquake of 5.1 magnitude occurred inside Myanmar, with a depth of 2 kilometres, about 82km northeast of Mae Sai district, Chiang Rai, at 11.03pm on Monday and was felt in northern Thailand, the Thai Meteorological Department's Earthquake Observation Division reported.
The quake was reportedly felt in Mae Sai, Mae Lao, Muang, Mae Fah Luang, Wiang Chiang Rung, Chiang Saen and Phaya Mengrai districts of Chiang Rai; and Muang, Mae Ai and Fang districts of Chiang Mai.
The earthquake was followed by a number of aftershocks into Tuesday morning.
There were no immediate reports of damage.