Tens of thousands of workers have fled Thailand, most of them for homes in neighbouring Myanmar, after new labour regulations adopted by the military government sparked fear and panic among the migrant community.
Millions of workers from poor neighbours, such as Cambodia and Myanmar, form the backbone of Thailand's manual labour force, with industries such as the multi-billion-dollar seafood business heavily reliant on foreign workers.
However under a decree that came into effect on June 17, an employer who hires an undocumented foreign worker faces a fine of up to 800,000 baht ($30,720).
The penalty has some businesses scrambling to fire undocumented workers or get them registered.
About 60,000 workers left between June 23 and 28, and the number has risen since, an Immigration Bureau official said.
"They were of all nationalities, but the biggest group was from Myanmar," Deputy Commissioner Pornchai Kuntee told Reuters.
"They are probably very scared."
Since taking power in a 2014 coup, Thailand's ruling junta has attained varying degrees of success in campaigns to regulate the foreign workforce, spurred partly by media reports that unregulated workers faced exploitation by employers.
Following news of the exodus, the country late last week promised a 120-day delay in enforcing parts of the decree, including the heavy fines.
Geta Devi, 28, a Myanmar worker based in Bangkok, said some of her friends panicked over the decree, adding, "They went back to Myanmar."
Thai government trucks have been taking workers to the Myanmar town of Myawaddy — located 246 kilometres east of Yangon, and opposite the Thai town of Mae Sot — to be handed to Myanmar authorities, a Myanmar official said
It was unclear if they were leaving Thailand voluntarily.
Fleeing workers at risk of extortion
Since June 29, more than 16,000 people have returned home, Aung Htay Win, a labour ministry official who is coordinating Myanmar's response, said.
The figure included both legal and undocumented migrants fearing a crackdown, as well as some ordered home by employers, he said.
"Most of them stay for one night or so, then they continue to their home towns," he said, adding the workers were being temporarily housed in government buildings.
Since last week, up to 500 Cambodian migrant workers have returned home, said Chin Piseth, deputy chief of the Thai-Cambodia border relations office of the Cambodian army.
"According to reports I received, between 400 and 500 were deported," he told Reuters.
Such mass movement leaves undocumented workers vulnerable, said Andy Hall, a migrant workers' rights expert who has monitored such migration in Thailand for over a decade.
"It's clear to me tens of thousands of migrants only move like this after instigation," Mr Hall told Reuters.
Despite the threat of punishment, "corrupt officials" would try to seek bribes, he said.
"Mass profit is to be made in a short time from the panic."
Police trying to extort money from employers or migrant workers will be punished, Thai police chief Chaktip Chaijinda warned last week.
Thailand has more than 3 million migrant workers, the International Organization for Migration says, but rights groups put the figure higher.