When the South Korean delegation briefed Trump in the Oval Office, he was joined by a number of top advisers, including Defense Secretary Jim Mattis, National Security Adviser H.R. McMaster, chief of staff John Kelly and the director of national intelligence, among others, according to a senior Trump administration official who briefed reporters after the announcement. The official, who was not authorized to discuss the sensitive diplomatic issue by name and spoke on condition of anonymity, said there was no letter from Kim to Trump, just an oral briefing from the South Korean officials.