United Nations Secretary-General Ban Ki-moon expressed “deep concern” Thursday over the fate of North Korean defectors in China, which has emerged as a key diplomatic issue between Seoul and Beijing, according to his office.

In a meeting with visiting South Korean Foreign Minister Kim Sung-hwan, Ban “shared the deep concern with the Foreign Minister about the dislocated people from the DPRK, and encouraged the concerned parties to do their utmost to find a mutually agreeable solution,” the U.N. leader’s office said in a press release.

Ban, formerly a South Korean foreign minister, also reiterated his worries about the severe food and nutrition problems in the North and welcomed some progress in talks between the U.S. and North Korea, Ban’s office said.

The South’s foreign minister, meanwhile, told reporters that the Seoul government and the U.N. agreed to continue consultations over the humanitarian issue in the North.

Kim said Seoul was trying to confirm press reports of the pending repatriation of North Koreans caught by Chinese authorities.

He is scheduled to hold bilateral talks with Secretary of State Hillary Clinton in Washington on Friday. (Yonhap News)