Defense Secretary Robert Gates has arrived in Iraq to meet with commanders as the U.S. prepares to cuts its troops levels and begin to pull forces out of the cities. The unannounced visit on Saturday comes as President-elect Barack Obama prepares to take office and begin to implement what many expect will be an accelerated withdrawal of troops, according to a report of Associated Press. During Obama's presidential campaign, he said he wanted combat troops out of Iraq in 16 months, but he has also said he would listen to the advice of his commanders on the ground. A security agreement between the U.S. and Iraq mandates that combat forces leave the cities by next June, and leave Iraq in three years.