Christopher Hill, the US pointman on North Korea, headed on Tuesday from Tokyo to Seoul, the second stop on a tour to ratchet up the pressure after Pyongyang's nuclear test, a US embassy official said.
Hill is touring East Asia ahead of US Secretary of State Condoleezza Rice, who will head this week to the four other countries—China, Japan, Russia and South Korea—involved in stalled disarmament talks with North Korea.
In Japan, which has supported the tough US line on North Korea, Hill called for all countries to abide by the weekend's UN Security Council resolution that imposed sanctions on the communist state after its nuclear test.
South Korea, while supporting the resolution, has preferred a "sunshine policy" of trying to engage its communist neighbour.