A shallow magnitude 6.1 earthquake hit northwestern Laos near the Thai border early on Thursday, the United States Geological Survey reported.
There were no immediate reports of damage after the earthquake hit at 6:50am local time (23:50 GMT on Wednesday).
But shaking could be felt more than 700 kilometres (435 miles) away in the Thai capital Bangkok.
“The shaking … was the main shock from a quake in Laos at 6:50am and was felt in northern and northeastern Thailand and Bangkok and suburbs,” said Sophon Chaila, an official at the Thai Meteorological Department.
“As of now there is no report of damage,” Sophon added.
Residents in the Vietnamese capital Hanoi also felt buildings sway.
“The ceiling lights were shaking quite strongly. I felt dizzy and scared,” said Hanoi resident Tran Hoa Phuong, who felt the earthquake in her 27-storey apartment building.
It hit about three hours after a magnitude 5.7 earthquake struck the same region of Laos, near the site of the controversial Xayaburi dam project.
Information is slow to trickle out of the closed communist state, and there were no reports of damage or injuries after the twin quakes hit.