BAGHDAD — President Obama will deploy 560 more troops to Iraq to help retake Mosul, the largest city controlled by the Islamic State, Defense Secretary Ashton Carter announced Monday.

It is the latest escalation of the US role in the Iraq war by Obama, who ran for office on a pledge to end America’s involvement in the conflict.

Many of the new troops will be at an airfield 40 miles south of Mosul that was reclaimed by Iraqi soldiers Saturday. They will bring the official number of US service members in Iraq to 4,647, far fewer than the 130,000 the United States had in the country a decade ago. Including commandos and service members in the country for less than four months brings the total to more than 5,000.

US commanders plan to use the base, called Qayara Airfield West, as a staging area to provide support to Iraqi forces as they try to retake Mosul.

The Iraqis have struggled to move troops, resources, and equipment — tasks that will become even harder as their forces move closer to Mosul, which is 250 miles from their major supply hubs in Baghdad.

“We need to move to this place to be as close to the fighting as we have been,’’ said Lieutenant General Sean B. MacFarland, head of US forces in Iraq.

Some of the US troops who will be stationed at the airfield specialize in infrastructure support, such as building bridges — a skill the Iraqis will need for the assault on Mosul. The Islamic State has destroyed many bridges around the city since it took control in 2014.

The new troop deployment comes two years after Obama said that while the United States would help the Iraqi military reclaim territory from the Islamic State, those efforts would “not involve American combat troops fighting on foreign soil.’’ Since then, he has steadily increased the number of troops in Iraq and given them more authority. Three service members have been killed.

In April, Carter visited Baghdad to announce Obama had given US military advisers the approval to work closer to the front lines with smaller units of Iraqi forces. As part of that announcement, Obama deployed an additional 217 troops, raising concerns among many Americans who believe the United States is on a never-ending mission in Iraq.