US Republican presidential candidate Senator John McCain (R-AZ) unbuckles his flight helmet as he arrives at Sather Air Base in Baghdad, March 16, 2008. Picture taken March 16, 2008. (Xinhua/Reuters Photo) 

But McCain reiterated that he would not advocate the withdrawal of US troops from Iraq. His Democratic rivals Barack Obama and Hillary Clinton have both pledged to gradually withdraw US troops if elected.

Howard Dean, chairman of the Democratic National Committee, criticized McCain's speech as "empty rhetoric" that does nothing to distance him from the policies of the Bush administration.

"His new appreciation for diplomacy has no credibility after hemimicked President Bush's misleading case for a unilateral war of choice when it mattered most," Dean said.

McCain was on his first visit to California after becoming the presumptive Republican presidential nominee last month.

(Xinhua News Agency March 27, 2008)