Details of his itinerary in Seoul have yet to be disclosed except for talks with his South Korean counterpart Kim Hong-kyun on Wednesday.

"He is to hold talks with Kim and have a working lunch with him and other officials," an official said on the customary condition of anonymity.

Yun comes to South Korea amid growing concerns over the North's repeated provocations. The North conducted two nuclear tests last year alone and didn't respect multiple resolutions or sanctions, as it continued to carry out provocations, including the launch of four ballistic missiles on March 6.

The North said on Sunday that it recently tested a new high-thrust rocket engine, raising speculation that Pyongyang might be seeking near-future provocations despite warnings by the international community.

Yun came right after Secretary of State Rex Tillerson visited South Korea last week as part of his first three-country Asian tour that also took him to Tokyo and Beijing.

Tillerson talked tough on the North, saying that "all options" including the use of military force remain on the table in dealing with the regime. He also said a "new approach" is necessary for the North, while emphasizing that conditions for talks with Pyongyang are "not ripe."

The former oil executive's remarks were closely scrutinized for any glimpse into Donald Trump's North Korea policy, which is said to be in the final stages of review.

In Seoul, Yun is expected to share the results of Tillerson's discussions in China with South Korea and exchange views on how to coordinate policies against Pyongyang.

Yun and Kim met in late February in Washington to discuss the North's nuclear and other pending issues. The US envoy came to Seoul in December but his forthcoming visit will mark the first of its kind under Donald's administration. (Yonhap)