Six North Korean defectors were arrested in China's Hebei Province last weekend and are at risk of being sent back to the repressive state. They were arrested with two other people who were helping them. Last month, another two South Koreans who help North Korean defectors were arrested in China.

There are fears that Chinese authorities could come down harder on people fleeing North Korea amid a spat with South Korea over the stationing of a U.S. Terminal High-Altitude Area Defense battery here.

A source on Thursday said the six defectors, all women, left Shenyang in China's Liaoning Province on Saturday night aboard a rented bus and arrived in Hebei on Sunday. They were accompanied by two Chinese people smugglers. But they were arrested at a police checkpoint.

"Out of all of the vehicles that were passing that checkpoint, police stopped the bus carrying the defectors, which suggests that they were tipped off."

The women had apparently been hiding in China for between one and five years after fleeing from the North and were now setting off on the arduous trip across China and the "green" border into Southeast Asia.

China's hardline policy of treating North Korean defectors as illegal aliens and sending them back had eased considerably since 2014, when Seoul-Beijing relations were at their peak.

But South Korean human rights groups say China has turned hardline again since Seoul agreed late last year to let the U.S. station the THAAD battery here.

