More than 600 migrant workers from Myanmar who were arrested while attending a traditional celebration near Bangkok are to be deported, Thai police and immigration officials said on Monday.
Police Colonel Krisakorn Pleetanyawong, head of Sam Pran district in Nakhon Pathom province, said police on Sunday arrested 674 Karen and ethnic Burmese after 10,000 people gathered at the sports ground of the Royal Police Cadet Academy.
"We didn't know there would be a big meeting of Myanmar workers here," he said, adding that one Thai had been granted permission to hold an annual good luck celebration in the compound about 70 kms from Bangkok.
Sixty-seven of the workers were released, Krisakorn said, but 426 men and 181 women have been referred to the Immigration Bureau for deportation.
He said 181 of them did not have work permits and were in Thailand illegally, while the rest were outside the area permitted by their work permits.
Sunai Phasuk, spokesman for Human Rights Watch in Thailand, urged leniency and said most workers were in the country legally and believed they had permission to hold the celebration.
"They did violate the law, but the government should look into the human side of the case - these people didn't harm anyone," he told the agency.
"They were only trying to commemorate a cultural event."
He also warned that the Karen members of the group could face political persecution on their return to Myanmar.
"If they fail to return to Thailand they may be in physical danger in the Karen State as a result of conflict and they may be subject to political persecution," he said.
Thousands of ethnic Karens flee fighting in military-run Myanmar every year. Human rights groups accuse the army of killing civilians and torching villages in their efforts to quell the Karen National Union, the oldest and largest rebel force, which is still battling the junta.
Myanmar -- formerly known as Burma -- is also one of the poorest countries in the world, and migrant workers flock to Thailand in search of a better life.
Immigration officials told the agency that all 607 migrant workers would be sent back to Myanmar as soon as possible. The officials will consider which areas are safe for them to return home.
The arrests Sunday came a day before the arrival in Thailand of UN High Commissioner for Refugees Antonio Guterres, who is here on a four-day mission and will visit Tham Hin refugee camp on the Myanmar border.
Nearly 10,000 ethnic Karen who fled fighting are currently living in the overcrowded camp in western Ratchaburi province, but 1,700 will soon be relocated to the United States and Australia after the US waived a law which deemed them terrorism supporters.