BALAD, Iraq, (Reuters) – U.S. Defense Secretary Robert Gates arrived in Iraq on Saturday ahead of a gradual drawdown of U.S. military might in the country.

The 149,000 U.S. soldiers in Iraq are preparing to pull out of cities and towns by the middle of next year and withdraw entirely from Iraq by the end of 2011 under a U.S.-Iraq security pact that enters into force in January.

In recent months there has been a sharp decline in the violence that raged after the 2003 U.S.-led invasion.

Gates arrived at a U.S. air base at Balad, north of Baghdad, after a visit to Bahrain and Afghanistan, where 65,000 international troops, including 30,000 from the United States, are struggling to defeat a reinvigorated insurgency by Taliban and other rebels.

The United States wants to send more troops to Afghanistan but its ability to do so largely depends on being able to cut back in Iraq.

Officials have warned violence in Iraq could surge again ahead of provincial elections in January, a general election later next year, and as U.S. troops hand increasing responsibility for security to Iraqi police and soldiers.

“There probably will be considerable interest in keeping as much of our strength there (in Iraq) as we can through the provincial elections and probably for some period of time after that,” Gates said on Wednesday as he began his trip. “The fact that the SOFA requires us to be out of all populated areas by the end of June really marks a pretty significant transition of the mission,” he added, referring to the status of forces agreement that is part of the pact. He said that if all Iraq’s 18 provinces were under the control of Iraqi forces at that time, rather than U.S. troops, then the U.S. role would become more one of training and equipping than of combat.

Gates was due to meet with the commander of U.S. forces in Iraq, General Ray Odierno, and then visit troops at Balad.