The special US envoy for North Korea returned to Seoul on Friday after talks with North Korean officials in Pyongyang to set up the agenda for the second summit between President Donald Trump and Kim Jong-un. Stephen Biegun’s three-day trip was expected to have explored a wide range of denuclearization issues in preparation for the summit in Vietnam on February 27 and 28, AFP said. Biegun landed at Osan US Air Base Friday evening, Foreign Ministry spokesman Noh Kyu-duk said. It is not known whether Biegun met with Kim, with North Korean media silent on his visit. The envoy is expected to share details of his Pyongyang meetings with his South Korean counterpart Lee Do-hoon and Foreign Minister Kang Kyung-wha on Saturday.