The U.N. special envoy for North Korean human rights said the U.N. is “analyzing multiple sources” to determine if China is forcibly repatriating North Koreans detained in the country as the DPRK opens its borders.

“We are analyzing multiple sources. But what I can say to you is that I am very concerned,” Elizabeth Salmon said at a press conference in Seoul on Tuesday, marking the end of her second official visit to South Korea.