The United States remains hopeful about a planned June 12 summit with North Korea but has not made concessions in advance of the historic meeting to discuss denuclearization, US Vice President Mike Pence said on Tuesday.

Hours before South Korean President Moon Jae-in was to meet with US President Donald Trump at the White House, Pence told Fox News Radio: "Plans continue to go forward for a summit. We remain open to it, we remain hopeful."But let me very clear: nothing has changed about the policy of the United States of America. There have been no concessions offered and none given."