Myanmar in southeast Asia was hit by a 7.7 magnitude earthquake on Friday, seismologists said, causing a high-rise building under construction to collapse in Thailand’s capital Bangkok. It was shortly followed by another 6.4 quake.

Bangkok police confirmed the building collapse, but possible casualties are not yet known. Multiple videos shared on social media appeared to show the collapse.

One dramatic video circulated on social media showed the multi-story building with a crane on top collapsing into a cloud of dust, while onlookers screamed and ran.

Police told The Associated Press they were responding to the scene near Bangkok’s popular Chatuchak Market, and had no immediate information on how many workers were on the site at the time of the collapse.

Khaosod, a Thai newspaper, reported that 43 people were unaccounted for after the building collapsed.

The U.S. Geological Survey recorded the epicenter of the first earthquake at 16km northwest of Sagaing in Myanmar, and it had a depth of 10km. The second occurred 18km south of Sagaing and had a depth of 10km.

This is close to the city of Mandalay, the second largest in Myanmar, which has a population of around 1.6 million, according to UN estimates.

In the capital Naypyitaw, the quake damaged religious shrines, sending parts toppling to the ground, and some homes. Further reports of damage were not immediately available from Myanmar, which is embroiled in a civil war.

But buildings swayed in Thailand’s capital, Bangkok, more than 600 miles south of the epicenters. There are reports of damage caused by the quakes in Thailand shared by users across social media.

The quake was also forceful enough to send water sloshing out of pools in the city, some high up in high-rises, as the tremor shook.

The greater Bangkok area is home to more than 17 million people, many of whom live in high-rise apartments.

Alarms went off in buildings as the earthquake hit around 1:30 p.m. local time, and startled residents were evacuated down staircases of high-rise condominiums and hotels in densely populated central Bangkok.

This is a developing story and more information will be added soon.

This article includes reporting by The Associated Press.