Chung Eui-yong, head of the presidential National Security Office, Suh Hoon, the chief of the South's National Intelligence Service, and other delegates arrive at a military airport in Seongnam
By Christine Kim and Steve Holland
SEOUL/WASHINGTON (Reuters) - Two South Korean envoys will travel to the United States on Thursday to meet National Security Adviser H.R. McMaster and other officials to discuss this week's meeting with North Korean leader Kim Jong Un, officials in Seoul and Washington said.
National Security Office head Chung Eui-yong and National Intelligence Service chief Suh Hoon will also speak with other department heads and later possibly meet either U.S. President Donald Trump or Vice President Mike Pence, a South Korean administration official said on Thursday on condition of anonymity.
The official said Chung had already spoken to McMaster on the phone shortly after completing this week's visit to North Korea.
The South Korean envoys are expected to brief U.S. officials on North Korea's stance on possible future talks with Washington and its apparent willingness to suspend nuclear tests if the security of the North's government is assured.
U.S. Defense Secretary Jim Mattis was guarded when asked on Wednesday about the prospect of North Korean engagement.
"Obviously we're cautiously optimistic that there is some forward progress here," Mattis told reporters at the Pentagon.
"But we've been optimistic before so we're going to have to watch actions and see if they match words," he said.
Tensions over North Korea's nuclear and missile programmes rose to the highest level in years in 2017. Pyongyang pursues its weapons programmes in defiance of U.N. Security Council resolutions, with shrill, bellicose rhetoric coming from both Kim and Trump.
North Korea has boasted of its plans to develop a nuclear-tipped missile capable of reaching the mainland United States. However, fears of all-out war eased last month, coinciding with North Korea's participation in the Winter Olympics in the South.
Chung and Suh were part of a delegation that travelled to Pyongyang earlier this week in the first encounter between South Korean government officials and Kim Jong Un, where the North Korean leader said he was open to denuclearisation talks with the United States.
They also agreed the two Koreas would hold their first summit in more than a decade in late April. South Korean President Moon Jae-in has said sanctions should not be eased for the sake of talks and that nothing less than denuclearisation of North Korea should be the final goal for talks.
A senior U.S. administration official said on Thursday no decision on the possibility of the United States joining a summit of North and South Korea was expected to be made at this week's meeting with McMaster. Those discussions would be conducted in private among U.S. officials, the source said.
Chung will visit China and Russia after returning from the United States, while Suh Hoon will head to Japan to brief officials.
(Reporting by Christine Kim in SEOUL and Steve Holland in WASHINGTON; Additional reporting by Philip Stewart; Editing by Richard Chang and Paul Tait)