Seoul is the first leg of Bolton's Asian trip that includes stops in Japan and China.

During his four days in Seoul, Bolton, the under secretary of state for arms control and international security, is to meet Foreign Minister Ban Ki-Moon and top security officials.

Bolton is considered one of Washington's more hawkish critics of Pyongyang.

When here last year he called North Korean leader Kim Jong-Il a "tyrannical rogue" and described life in the Stalinist state as a "hellish nightmare."

WAR.WIRE