President Lee Myung-bak (right) chairs a meeting of top brass Tuesday at the headquarters of the Defense Ministry in Seoul. He expressed his willingness to carry out a comprehensive reform of national security by saying, The sinking of the Cheonan was no accident. Left of the president are Defense Minister Kim Tae-young, Army Chief of Staff Gen. Han Min-goo and Air Force Chief of Staff Gen. Lee Kye-hoon.0