Observers said that the Korean-born Kim, who is known to have emigrated to the US when he was a high school student, might have been selected to assist the top US diplomat as he is fluent both in Korean and English, and has security clearance as an intelligence agent.

Andrew Kim previously served in senior CIA posts in charge of Korea and the Asia Pacific region, and is known for his deep knowledge of the North. His views are reportedly critical of the reclusive state.

The Korea center chief is also known to have gone to the same high school in Seoul as South Korea's chief presidential security advisor Chung Eui-yong and Suh Hoon, the director of Seoul's National Intelligence Service.

In a foreign press photo taken on Wednesday, Andrew Kim was seen greeting Pompeo at the Pyongyang airport, raising speculation that Kim might have arrived in the North earlier for working-level coordination.

Washington and Pyongyang are expected to announce the venue and date for their highly publicized summit soon. Trump has ruled out the inter-Korean truce village of Panmunjom as the venue, though he earlier considered it as a possibility. (Yonhap)