President Donald Trump and first lady Melania Trump visit with members of the military at a dining hall at Al Asad Air Base, Iraq, Wednesday, Dec. 26, 2018. In a surprise trip to Iraq, President Donald Trump on Wednesday defended his decision to withdraw U.S. forces from Syria where they have been helping battle Islamic State militants. (AP Photo/Andrew Harnik)

President Trump said he has no plans to withdraw American forces from Iraq, a week after announcing a surprise pullout of troops from Syria and ordering the Pentagon to bring home roughly half of the American forces deployed to Afghanistan.

The decision allows the United States to maintain a presence in the heart of the Middle East and a bulwark against Iranian influence, while also keeping a nearby staging ground should American troops be forced to reenter Syria and engage a resurgent Islamic State.

A longer-term presence in Iraq provides Trump with a hedge against his withdrawal from Syria, a decision that was widely opposed by his advisers and which led to the resignation of his defense secretary, retired Marine Corps Gen. Jim Mattis.

The development also suggests that Trump’s proclamation of victory over the Islamic State in a video message from the White House lawn last week had been overstated. Trump said during a visit to Iraq on Wednesday that a presence in the country would enable the United States to reenter Syria if need be, suggesting that concerns persist about the possibility of the Islamic State regrouping there.

“In fact, we could use this as the base if we wanted to do something in Syria,” Trump said during Wednesday’s unannounced visit to al-Asad Air Base in western Iraq, between Baghdad and the Syrian border.

He was accompanied by first lady Melania Trump. Trump traveled with a small group of journalists, who were ordered for security reasons not to report that he was in Iraq until he had finished delivering his remarks to the troops, roughly three hours into his visit to the base. Air Force One landed at Joint Base Andrews, Maryland, at 5:12 a.m. EST, the Associated Press reported.

The decision to remain in Iraq also highlighted a contradiction in Trump’s messaging about the broader U.S. military presence in the Middle East. He said last week that U.S. troops would be coming out of Syria because victory had been achieved over the Islamic State. But the mission of the roughly 5,200 U.S. troops deployed to Iraq is to support government forces in their fight against the Sunni extremist group, which wouldn’t need to continue if a lasting victory had been achieved. U.S. forces remain in Iraq with the permission of the government, unlike in Syria, where the presence of American troops has been complicated by an alliance with a local militia.

Trump’s announcement about Iraq comes at a moment of deep uncertainty at the Pentagon, which was thrown into turmoil last week by the president’s surprise decisions on the future of American involvement in the Middle East and South Asia, as well as Mattis’s resignation.

The Defense Department has declined to offer details about the timing of the Syria withdrawal or whether the air campaign against the Islamic State in that country will continue apace. Neither the White House nor the Pentagon has made an announcement about Trump’s order to withdraw roughly half of U.S. troops from Afghanistan. On a trip to the region over the holidays, the chairman of the Joint Chiefs of Staff, Gen. Joseph F. Dunford Jr., dismissed reports of the order as “rumors.”

After pulling U.S. forces out of Iraq in 2011, President Barack Obama ordered them back to the country at the Iraqi government’s request in 2014, when the Islamic State was seizing cities across the nation and sweeping toward Baghdad. Since then, U.S.-backed coalition forces have successfully rolled back nearly all of the Islamic State’s self-declared caliphate in Syria and Iraq, including the key cities of Raqqa and Mosul, which served as the group’s main power centers.

Still, worries about an Islamic State comeback are pervasive. Official assessments from the U.S. government and the United Nations have indicated that some 30,000 Islamic State fighters may still remain at large in Syria and Iraq. The group’s leader, Abu Bakr al-Baghdadi, hasn’t been caught and is presumed to be alive.

Iraqi security forces have been conducting frequent raids and arresting alleged members and leaders of the Islamic State in recent months, underscoring how the fight against the militants has shifted from combat to intelligence operations.

The group has still been able to mount low-level bombings and attacks, largely outside major cities. Iraqi military officials say the threat is contained but express concern that any reduction in coalition support could give the militants an opening to reemerge.

Iraq’s previous prime minister, Haider al-Abadi, was a strong supporter of the American presence in Iraq – a view shared by the top leadership of Iraq’s security forces. His successor, Adel Abdul-Mahdi, has not said explicitly that he wants U.S. forces to stay but also hasn’t indicated that he would support a reduction in troop levels.

Trump’s decision not to meet any Iraqis during Wednesday’s visit risks jeopardizing support for the U.S. troop presence, which faces opposition in particular from pro-Iran elements within the country.

In a statement issued following Trump’s appearance, Abdul-Mahdi said his office had been informed of the president’s desire to arrange a visit, which was supposed to include a formal meeting between the two leaders. He said “a divergence of views” on organizing the meeting led to its replacement by a telephone conversation. A person familiar with the planning, who spoke on the condition of anonymity to discuss the president’s schedule, said the White House gave the Iraqis no advance notice and asked Iraqi officials to meet Trump at the air base – a request the Iraqis balked at.

Tension over the U.S. troop presence in Iraq has been exacerbated by the increasing influence of Iran in the country, particularly after Iranian-backed militias played a role in the rollback of the Islamic State and won a significant number of seats in parliament this year.

Sabah al-Saedi, head of a parliamentary bloc backed by Shiite cleric Moqtada al-Sadr, called for an emergency session of the legislature to condemn Trump’s “blatant violation of Iraq’s sovereignty.”

In a statement, he said Trump was “acting as if Iraq is a state under his authority” and must be informed “of his limits. The U.S. occupation of Iraq is over.”

Saedi added that the withdrawal of U.S. forces from Syria is not a justification to keep American troops in Iraq. Sadr, whose militia was responsible for the deaths of hundreds of American troops at the height of the Iraq War, won the most seats in Iraq’s election for his movement earlier this year and is a frequent critic of both American and Iranian involvement in Iraq.

The Washington Post’s Mustafa Salim in Baghdad contributed to this report.