A school operated by the Border Patrol Police in Bor Kluea district of Nan is damaged after an earthquake in Laos near the Thai border in the northern province. (@Ruamduay Twitter)

A shallow 6.1-magnitude earthquake hit northwestern Laos near the Thai border early Thursday, the United States Geological Survey reported, alarming locals who felt buildings shake as far away as Bangkok.

There were no immediate reports of damage after the quake hit at 6:50 a.m. (2350 GMT Wednesday).

But tremors could be felt more than 700 kilometers (435 miles) away in the Thai capital, where Pope Francis is currently on a four-day visit.

“The shaking… was the main shock from a quake in Laos at 6:50 am 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 said.

The department said the quake affected nine provinces in Thailand and there were four lesser aftershocks. It also became a top trending topic on Twitter in Thailand.

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 5.7-magnitude earthquake struck the same region of Laos, near the site of the large Xayaburi dam project, which reported no damage so far.

Information is slow to trickle out of the closed communist state, and there were similarly no official reports of damage or injuries after the twin quakes hit early Thursday.

Impoverished Laos has ploughed ahead with ambitious dam-building projects that critics say lack transparency and stringent safety measures.

The cost was laid bare last year when a massive hydropower project collapsed in southern Laos, killing dozens and leaving thousands homeless.

Pope Francis arrived in Bangkok on Wednesday and has a busy agenda Thursday meeting officials and the Thai king before he leads a mass in the evening.

There was no word from his team on whether he felt the quake.

Powerful earthquakes occasionally strike hard in Southeast Asia.

In 2016 a 6.8-magnitude quake struck Myanmar, killing at least three people and damaging temples in the ancient temple town of Bagan.