“We are trying to identify the bodies and also trying to contact the Myanmar Consulate in order to identify the bodies,” Colonel Krissana said. “They are Buddhists, so we’ve got to send them back to their hometown for religious ceremonies there.”

Kittasak Boonchan, an administrator of a rescue group in Tak Province, said he arrived at the scene around 2:30 a.m., about 20 minutes after the first rescue team.

The burning bus was about 15 miles from the rescue team’s base, he said, delaying their response.

“When we got there, the flames were so strong,” Mr. Kittasak said. “People who couldn’t get out of the bus were writhing in pain in the flames.”

Most of the survivors had only minor injuries, but one person was badly burned and cut by a mirror, he said.