U.S. President Barack Obama made an unannounced visit to Baghdad today, marking a new chapter in his strategy to wind down the unpopular war in Iraq and shift the United States' military focus to Afghanistan.

The White House said that Obama would meet U.S. commanders and troops, and speak to Iraqi leaders by telephone.

He would call the Iraqi leaders rather than see them in person because poor visibility prevented helicopter travel, White House spokesman Robert Gibbs said.

Flying secretly from Istanbul at the end of his first major international tour, Obama was to visit the scene of a war that he inherited from his predecessor, George W. Bush. It was Obama's first visit to Iraq since before his November 2008 election victory, which was bolstered by his campaign pledge to start bringing U.S. troops home.

Asked why Obama had come to Iraq, Gibbs said "there are several important reasons, not the least of which is to see and spend some time with the men and women who are serving our country honorably here."