AL ASAD AIR BASE, IRAQ (WASHINGTON POST, BLOOMBERG, REUTERS, AFP) - United States President Donald Trump greeted American troops on an unannounced trip on Wednesday (Dec 26) to Iraq, where he defended his decision to withdraw forces from neighbouring Syria and declared that the Islamic State in Iraq and Syria (ISIS) was "very nearly defeated".

It was his first visit to a conflict zone as commander in chief.

The President used his visit to Al Asad Air Base to amplify his call to draw down the US presence in foreign wars and assert his personal influence over the military at a moment of tremendous turmoil at the Pentagon.

After months of public pressure for him to spend time with troops deployed to conflicts in the Middle East and Central Asia, Mr Trump touched down at the joint US-Iraqi base west of Baghdad after a secret flight from Washington.

Accompanied by First Lady Melania Trump, the President sounded a triumphant note as he addressed US service members on the day after Christmas.

"We're no longer the suckers, folks," he said. And he warned that he was committed to withdrawing troops from foreign wars even when his administration's experts object.

"The United States cannot continue to be the policeman of the world," Mr Trump said.

"It's not fair when the burden is all on us, the United States."

Mr Trump also bemoaned US commitments overseas.

"We are spread out all over the world," he said. "We are in countries most people haven't even heard about. Frankly, it's ridiculous."

After a briefing with military and diplomatic leaders on the ground, Mr Trump strongly defended his decision to pull out of Syria.

"We want peace and the best way to have peace is through strength," he told troops wearing camouflage fatigues in a hangar as he concluded his visit. He said some troops "can now return home to their families".

"Our presence in Syria was not open ended and it was never intended to be permanent," he added.

But he said he had no plans to withdraw American forces from Iraq, which he said the US could use as a staging ground in the heart of the Middle East from which to combat Iran, or someday re-enter Syria.

"If we see something happening with ISIS that we don't like, we can hit them so fast and so hard they really won't know what the hell happened," Mr Trump said, according to Bloomberg News.

Mr Trump told reporters travelling with him that he would deny any request from generals to extend the US operation in Syria, where roughly 2,000 troops are deployed.

"They said again, recently, 'Can we have more time?'" Mr Trump said of US generals. "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."

It was his first trip to a conflict zone nearly two years into his presidency and the couple stayed for a little more than three hours.

Mr Trump said that a "couple" of trips had been previously set up but cancelled as word got out.

"Pretty sad when you spend US$7 trillion in the Middle East, and going in has to be under this massive cover with planes all over and all of the greatest equipment in the world, and you do everything to get in safely," he said.

Mr Trump said he considered the safety risks in making his first trip to a war zone.

"I had concerns about the institution of the presidency," he told reporters.

"Not for myself personally. I had concerns for the first lady, I will tell you. But if you would have seen what we had to go through in the darkened plane with all windows closed, with no light anywhere. Pitch black. I've been on many airplanes. All types and shapes and sizes... So did I have a concern?" he continued. "Yes, I had a concern."

Mr Trump has drawn fire from some in the US military for not having visited US troops in conflict zones since taking office in January 2017, particularly after he cancelled a trip to a World War I cemetery in France last month due to rain.

While there has been no full-scale violence in Iraq since ISIS suffered a series of defeats last year, about 5,200 US troops train and advise Iraqi forces still waging a campaign against the militant group.

On his way home from Iraq, Mr Trump will stop to visit troops at Ramstein Air Base in Germany.

Mr Trump was looking for some positive headlines after days of turmoil over his decisions to withdraw all US troops from Syria, pull out half of the 14,000-strong contingent in Afghanistan, and push out Defence Secretary James Mattis two months earlier than planned for criticising his policies.

Many Republican and Democratic lawmakers have heaped scorn on Mr Trump for his sudden order last week to withdraw from Syria.

Mr Trump's critics have said that the fight is far from over and the withdrawal leaves allies in the lurch.

One of those critics was Mr 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 US allies. Mr Mattis had planned to leave at the end of February but Mr Trump forced him to go on Jan 1 after his resignation letter.

The President has also faced negative headlines for wanting to pull troops from Afghanistan where they have been since 2001. He has questioned how long troops there should have to remain in what has become America's longest war.

Mr Trump was supposed to meet Iraqi Prime Minister Adel Abdul Mahdi, but in the end, they spoke only by telephone.

Mr Abdul Mahdi's office said there was "a disagreement over how to conduct the meeting". Iraqi lawmakers said the Prime Minister declined Mr Trump's request to meet him at the military base.

White House spokesman Sarah Sanders said the meeting was cancelled due to security concerns and the short notice of the trip, but she said they had a "great call" and that Mr Abdul Mahdi accepted Mr Trump's invitation to the White House in the New Year.

BUSH AND OBAMA

Mr Trump's unannounced visit to Iraq followed in the footsteps of two of his predecessors, Republican George W. Bush and Democrat Barack Obama, who both made surprise trips to see troops. For security reasons, the visits are usually kept secret until after the president arrives.

While in Iraq, Mr Trump spoke to military commanders and the US ambassador and, according to Ms Sanders, they "came up with a powerful plan that will allow us to continue our path to total victory" over ISIS.

Unlike Syria, Mr Trump said he had no plans to withdraw from Iraq.

Mr Trump has had an uneven relationship with America's military. He did not have to serve during the Vietnam War after being diagnosed with bone spurs in his heels.

As president-elect, Mr Trump was drawn to the brawn of the armed forces and stacked his first Cabinet with generals, many of whom have since left his administration.

He has also wanted to end protracted US involvement in overseas conflicts, and to force allies to pay more for the costs that he says fall disproportionately on American taxpayers, a point he made again on Wednesday.

Mr Trump spoke to troops gathered in a dining hall festooned with holiday decorations and teased soldiers about their favorite football teams.

To reporters, he lamented the wear and tear of overseas conflicts.

"It's time to get our young people out," he said.

"And I've been signing plenty of letters and I don't like sending those letters home to parents saying that your young man or your young woman has been killed.

"I don't like doing it. We've been doing it long enough."