U.S. Special Representative for North Korea Stephen Biegun has arrived in South Korea after completing his visit to North Korea. 

An American transport aircraft carrying Biegun was known to have departed from Pyongyang earlier Friday before landing at the U.S. Osan Air Base at around 7 p.m. 

During his three-day stay in Pyongyang, the envoy met with his North Korean counterpart Kim Hyok-chol, possibly to coordinate the wording of the agreements to be released after the second U.S.-North Korea summit scheduled for February 27th and 28th in Vietnam.

With the details of Biegun's talks in the North yet unknown, attention is being paid to how much the two sides succeeded in ironing out differences over the North’s denuclearization and corresponding measures from the U.S. 

There is strong speculation, however, that the two countries will hold additional working-level talks before the second summit to further narrow differences over key issues. 

It is believed Biegun will report to Washington on the outcomes of his trip before briefing Seoul in a meeting with his South Korean counterpart Lee Do-hoon expected to be held Saturday morning. Biegun and Lee will also likely discuss strategies for follow-up negotiations with Pyongyang. 

The senior U.S. envoy is also expected to meet with South Korean Foreign Minister Kang Kyung-wha.