BANGKOK — International aid began to arrive in Myanmar on Saturday as rescuers searched for survivors after a powerful earthquake devastated the Southeast Asian nation amid concerns the number killed would soar.

The death toll in Myanmar jumped to 694 with 1,670 injured, the military government said, up sharply from the 144 dead that state media reported on Friday.

“Infrastructure such as roads, bridges, and buildings were affected, leading to casualties and injuries among civilians. Search and rescue operations are currently being carried out in the affected areas,” the junta said in a statement issued on state media.

The junta leader, General Min Aung Hlaing, had warned on Friday of more deaths and injuries as he invited “any country” to provide help and donations.

A Chinese rescue team arrived on Saturday while Russia and the U.S. offered aid in the disaster, which struck at lunchtime on Friday and damaged hundreds of buildings in neighboring Thailand.

The United States Geological Survey’s predictive modeling estimated the death toll could exceed 10,000 people in Myanmar, and that losses could be greater than the value of the country’s gross domestic product.

Susan Hough, a scientist in the USGS’s Earthquake Hazards Program, told Reuters it was difficult to predict an earthquake’s death toll, for various reasons including timing.

When an earthquake strikes during the daytime, as it did with the 7.7 magnitude quake in Myanmar, “people are awake, they have their wits about them, they are better able to respond,” she said.

Hough, who worked in Myanmar on the local seismology network, said the country’s mix of modern structures and traditional buildings would also play a role. Traditional buildings “are going to be less potentially deadly than concrete,” she said.

International aid arrives

Much of the devastation was in Myanmar’s second-largest city, Mandalay, close to the epicenter of the quake.

In the Thai capital Bangkok, 620 miles from the epicenter a rescue mission was stepped up on Saturday to find construction workers trapped under the rubble of a collapsed 33-story tower.

A 37-strong team from China landed in Yangon, Myanmar’s former capital, early on Saturday, carrying medicine and equipment to detect signs of life with them, the Chinese embassy said in a Facebook post.

Russia said it was sending 120 experienced rescuers as well as doctors and search dogs, state news agency TASS reported.

President Donald Trump said on Friday he had spoken with officials in Myanmar and that his administration would be providing some form of assistance.

Search for survivors in Thailand

Thai authorities said nine people had died and 101 were missing in Bangkok, mostly laborers trapped in the rubble of the collapsed tower.

“We will do everything, we will not give up on saving lives, we will use all resources,” Bangkok Governor Chadchart Sittipunt said at the site on Saturday, as excavators moved debris and drones scoured the rubble searching for survivors.

The Thai capital ground to a halt on Friday and Chadchart said hundreds of people had spent the night in city parks, but he said the situation was improving.