Andrew Kim, the former head of the CIA's Korea Mission Center, has had secret meetings with senior government officials here, including National Security Adviser Chung Eui-yong, a diplomatic source said Monday.

"Kim left the CIA late last year but is still advising the Trump administration as a top North Korea expert," the source said. "He has recently met Chung and other senior intelligence officers here to discuss strategies for negotiations with North Korea."

Kim reportedly met Chung and others in late July. He shared information with them about U.S. President Donald Trump's brief meeting with North Korean leader Kim Jong-un at the border truce village of Panmunjom in June. He also discussed a response to the North's ongoing missile provocations.