Thailand has in the last week helped facilitate the transfer of some 900 Chinese nationals who had been trapped in scam centers in a Myanmar border town back to China, Prime Minister Srettha Thavisin said Sunday.

Southeast Asia, including Myanmar, has become a hub for telecom and other online fraud, according to the United Nations, with hundreds of thousands of people trafficked by criminal gangs and forced to work in scam centers and other illegal operations.

The operation, which Thai police say started last Thursday and was completed on Saturday, involved transporting the Chinese nationals from Myanmar's border town of Myawaddy to an airport in the Thai border district of Mae Sot, where they were transferred to Chinese planes.

"This was a joint voluntary operation between three countries, China, Myanmar and Thailand," Prime Minister Srettha said.

"The process was done voluntarily, based on humanitarian principles, it was not forced," Srettha said, adding that Thailand had facilitated the transfer to the flights at Mae Sot.

Thai deputy police chief Surachae Hakparn said the operation involved 15 flights over three days to return Chinese scam victims to China.

The Chinese foreign ministry did not immediately respond to request for comment. Myanmar's military spokesperson also did not respond to a call seeking comment.

Last November Myanmar authorities handed over 31,000 telecom fraud suspects to China in a joint crackdown against online scams in Myanmar.

China and Myanmar also helped facilitate the transfer back to Thailand of more than two hundred Thais, both victims and those involved with telecom fraud gangs, who were trapped in fighting between Myanmar military and armed ethnic-minority groups in Laukkaing in Myanmar's northern Shan State.