SEOUL, South Korea (AP) — South Korea on Friday said it had expressed its concerns to China after assessing that it recently returned a “large number” of North Koreans, including escapees, back to their homeland.

Koo Byoungsam, spokesperson of South Korea’s Unification Ministry, which handles inter-Korean affairs, said Seoul did not have information on the exact number of North Koreans repatriated from northeast China or how many of them were “escapees, medical patients or criminals.”

His comments followed several media reports based on activist sources that alleged China recently returned hundreds of escapees back to North Korea where they would face the risk of persecution and harsh treatment.

“It appears to be true that a large number of North Koreans were repatriated to North Korea from China’s three northeastern provinces,” Koo said. “(Our) government’s position is that there should be no circumstances in which North Koreans living abroad would be forcibly repatriated back home against their will.”

Koo said Seoul “sternly raised the issue with the Chinese side” but did not specify how it communicated its concerns.

Human rights activists had warned that Chinese repatriations of North Korean escapees could increase as North Korea slowly reopens its borders after a prolonged COVID-19 shutdown. Some activist groups believe that the number of North Koreans detained as “illegal immigrants” in China could exceed 2,000.

When asked about the alleged repatriations of North Koreans on Thursday, Chinese Foreign Ministry spokesperson Wang Wenbin did not confirm the reports but said Beijing has been “properly” handling North Koreans who illegally entered the country based on “relevant domestic laws, international law and humanitarian principles.”

Citing an activist account, the Human Rights Watch in a report on Thursday alleged that China this week used several vehicle convoys to forcibly return more than 500 people who had escaped North Korea. The group said most of the returnees were women and expressed concerns that they were at “grave risk” of being detained in forced labor camps, and potentially face torture and other violence.