The Yomiuri Shimbun reported Friday that there was another group escape of North Korean workers in China last month.

The Japanese newspaper quoted sources with knowledge of North Korea-China relations as saying that eight North Korean female workers at a marine product-processing factory in Donggang, Liaoning Province escaped the workplace at the end of June.

The daily added a broker was likely to have guided them to a hiding place.

Yomiuri said after their escape, the North Korean authorities summoned around 100 other North Koreans from China, including the escapees’ colleagues.

The reported incident follows two other group escapes by North Koreans from China in April and May, through which a total of 16 female North Korean workers defected to the South.

Yomiuri said Pyongyang is strengthening the monitoring and oversight of its workers sent overseas to bring in cash for the regime by intensifying ideology education on them to secure their loyalty.

The Japanese paper, however, pointed out that such efforts have failed.