ANKARA-Amid crackdown on thousands of foreigners living illegally or accused of crime across Thailand, local police are suspecting a mass marriage scam involving hundreds of Indians, local media reported on Monday.

Thai police suspected a woman in her 70s who was seeking a spousal visa for her alleged Indian counterpart. The marriage proved to be fake, the Bangkok Post reported. This case led to a further investigation into such visa applications.

“Many of the sham marriage couples behaved suspiciously,” Immigration Bureau chief Surachate Hakparn told the newspaper.

According to the Nation newspaper, most of the accused used to make a living in Thailand as illegal moneylenders or salesmen for pay-by-installment goods such as clothing and electrical appliances.

“This is a threat to national security,” Hakparn said about the fake marriage scam.

Last Friday, Thai authorities said they already arrested nearly 7,000 foreigners in 43 different operations for illegal stay and other crimes in the country.

The news report said that around 8,000 Indian nationals reside in Thailand on spousal visas with Thai nationals.

"More than 200 of them have been found to have violated laws, including conspiring with Thai women to counterfeit marriage," the police official said. "All but 13 of them have been arrested, and 127 had their visas revoked and will be deported."

The newspaper noted that Indian nationals are often keen to stay in Thailand beyond the remit of their tourist visas, and "marriage can be used as a means to facilitate this."

However, police stressed that legal action is being taken against the Thai women as well, adding: “The court granted warrants for the arrest of 31 suspects [for false marriage] and 29, so far, have been detained.”

The official identified an Indian national as Vikrom Layehi, 35, who is accused of “acting as a broker to forge marriage” documents. “27 Thai women were also arrested on suspicion of marriage brokering,” Surachate added.

The fake marriage cases have caused concern among the bureaucracy in the military junta-ruled Buddhist-majority country. Top officials have called to follow state officials suspected of being involved in the crime closely.