'President Trump and the First Lady traveled to Iraq late on Christmas night to visit with our troops and Senior Military leadership to thank them for their service, their success, and their sacrifice and to wish them a Merry Christmas, ' White House Press Secretary Sarah Sanders said.
The drawdowns - and the abrupt way that they were announced - helped lead to the resignation of Trump's defense secretary, Jim Mattis, who has been one of the administration's key heavyweights.
Following his Iraq visit, Mr Trump tweeted: "Melania and I were honored to visit our incredible troops at Al Asad Air Base in Iraq".
Trump said the USA mission in Syria was to strip IS of its military strongholds - not to be a nation-builder.
President Trump's trip comes just days after he announced a drawn down of all US troops in Syria and the resignation of Defense Secretary James Mattis.
Last week, Trump announced the total withdrawal of U.S. troops from Syria and a draw-down of half the force now in Afghanistan, to shouts of protest from both Democrats and Republicans in Washington.
The President defended his decision to withdraw troops from Syria and vowed to continue the fight against ISIS from Iraq.
Both of Mr Trump's predecessors, Republican George W Bush and Democrat Barack Obama, made surprise trips to Iraq during their presidencies.
"We're, right now, the policemen of the world and we're paying for it", he said on a Christmas call with troops.
President Donald Trump visits with members of the military at a dining hall at Al Asad Air Base Iraq on Dec. 26 2018
"I made it clear from the beginning that our mission in Syria was to strip ISIS of its military strongholds", Trump told troop Al Asad Air Base. west of Baghdad. Mattis was expected to leave his post in February, but Trump forced him out early, saying he was replacing Mattis on January 1 with deputy defence secretary Patrick Shanahan in an acting capacity.
I'm sure we'll be hearing about it if he said anything to question the existence of Santa Claus during his visit.
Fifteen years after the 2003 invasion, the U.S. still has more than 5,000 troops in Iraq supporting the government as it continues the fight against remaining pockets of resistance by the Islamic State group.
One of those critics was Mattis, who said in a candid resignation letter last week that his views did not align with the president's, particularly in regard to the treatment of USA allies.
"We want peace and the best way to have peace is through strength", Trump told troops wearing camouflage fatigues in a hangar as he concluded his visit.
The president was joined at the air base by National Security Adviser John Bolton for meetings with political and military leaders.
Trump has described the USA involvement in Afghanistan as a "complete waste" and vowed to bring home American troops.
If it aided troop morale, there was no harm in this gesture other than its cost and the continuation of a long tradition of political exploitation of the US military.
He visited Afghanistan four times while in office.
Trump's trip to Iraq was shrouded in secrecy.
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At noon on Thursday, as the Senate's continuing resolution was being debated on the House floor, Trump met with House Speaker Rep. Some of his allies described the move as caving on his pledge and they expressed concern it could hurt Trump's 2020 prospects.