U.S. President Donald Trump and first lady Melania Trump speak to members of the U.S. military during an unannounced trip to Al Asad Air Base in Iraq on Dec. 26, 2018. (Xinhua/AFP)

WASHINGTON, Dec. 26 (Xinhua) -- The first visit of U.S. President Donald Trump to American troops deployed in the Middle East on Wednesday has been somehow clouded with secrecy.

Yet so far a major topic for him in Iraq was no secret -- the justification of his controversial decision to withdraw troops from Syria.

AN UNANNOUNCED VISIT

Earlier in the day, several media outlets reported that a plane carrying Trump and First Lady Melania have traveled to an unspecific destination.

The White House later confirmed Trump's hours-long visit to U.S. combat troops in Iraq on Twitter, as spokesperson Sarah Sanders said that the American first couple had traveled to Iraq on Christmas night to visit U.S. troops and military commanders to "thank them for their service, their success, and their sacrifice and to wish them a Merry Christmas."

Trump, for his part, capped the speculations with a tweet: "Melania and I were honored to visit our incredible troops at Al Asad Air Base in Iraq. GOD BLESS THE U.S.A.!"

Details of the trip could be read in the reports of journalists traveling with him that were later sent to the media. They said that Trump left the White House late on Tuesday "for an unannounced movement to Joint Base Andrews in Maryland."

"Air Force One was wheels up" on Wednesday and landed in the evening at the air base in Iraq, a joint U.S.-Iraqi military base west of Baghdad, the capital city of Iraq.

Asked why he chose Iraq in his first visit to overseas U.S. troops, Trump told reporters before a meeting with American military leaders there that "it's a place I have been talking about for many years."

While in Iraq, Trump addressed a group of some 100 U.S. soldiers, mostly troops engaged in combat operations in Iraq and Syria. However, a scheduled meeting with Iraqi prime minister was cancelled.

The visit came as a surprise for many as Trump had earlier been blasted by U.S. media as the "first president since 2002 not to visit troops on Christmas," a long tradition to boost morale overseas.

DEFENDING SYRIA WITHDRAWAL

Soon after landed in Iraq, Trump told the media and U.S. soldiers that he has given "the generals" multiple six month "extensions" to get out of Syria.

"They said again, recently, can we have more time? I said, 'Nope.' You can't have any more time. You've had enough time. We've knocked them out. We've knocked them silly," Trump said, obviously referring to the Islamic State.

"I will tell you that I've had some very good talks with (Turkish) President (Recep Tayyip) Erdogan who wants to knock them out also and he'll do it. And others will do it to. Because we are in their region. They should be sharing the burden of costs and they're not," Trump added.

"The United States cannot continue to be the policeman of the world ... we don't want to be taken advantage of any more by countries that use us and use our incredible military to protect them. They don't pay for it, and they're going to have to," he said.

While promising a "strong deliberate and orderly withdrawal" from Syria, Trump said that "in Syria, Erdogan said he wants to knock out IS, whatever's left, the remnants of IS. And Saudi Arabia just came out and said they are going to pay for some economic development. Which is great, that means we don't have to pay."

On Dec. 19, the White House said that it has started returning U.S. troops home from Syria after claiming a victory in the fight against the Islamic State.

Trump tweeted one day later that Defense Secretary James Mattis will retire at the end of February, but changed his decision on Sunday by saying that he has picked Deputy Secretary of Defense Patrick Shanahan as the acting Pentagon chief, forcing the outgoing Pentagon chief to step down two months earlier than planned.

Speaking about the surprising change of leadership, Trump said that Shanahan could be in an acting capacity starting on Jan. 1 " for a long time," indicating that he is in no rush to name a new Pentagon chief.

Trump has never been a fan of sending U.S. troops for battles overseas. Ever since his campaign, he has urged bringing the "boys" back home, while senior national security officials, including Mattis, have advocated for a longer-term military deployment to secure anti-terrorism victory.

"We are spread out all over the world. We are in countries most people haven't even heard about. Frankly, it's ridiculous," Trump said, warning however that if there is a terror attack in the U.S., "nobody will ever have suffered the consequences they had suffered."

U.S. TO STAY IN IRAQ

During his stay in Iraq, Trump told the media that he had no plans to withdraw the some 5,200 U.S. soldiers from Iraq, a country he could use "to do something in Syria."

"We can use this as a base if we wanted to do something in Syria," he said. "If we see something happening with IS that we don't like, we can hit them so fast and so hard."

Trump's brief visit, together with his remarks, has sparked sharp criticism from Iraq's major congressional leader, who claimed that it may have blatantly violated the Iraqi sovereignty.

Sabah al-Saidi, head of the Islah bloc in Iraq's parliament, reportedly said that an emergency session has been called to discuss Trump's visit.

On his way back to the United States, Trump also stopped to visit troops at Ramstein Air Base in Germany.