US President Donald Trump has defended his decision to withdraw troops from the war-torn Syria, saying America cannot be the world's policeman, as he made his first unannounced trip to Iraq.
President Trump and First Lady Melania secretly left Washington on Christmas night and visited Iraq on Wednesday to deliver holiday greetings to US combat troops.
"President Trump and the First Lady travelled 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 in a tweet.
Trump delivered a speech to around 100 uniformed service members at an air base west of Baghdad where he defended his decision to pull American troops out of Syria.
"The United States cannot continue to be the policeman of the world," Trump told reporters soon after he addressed American soldiers.
He said the US could use Iraq as a regional launching pad to carry out operations against the ISIS and Syria.
Trump vowed that his administration will give a "harsh response" if America faced another terrorist attack.
"If anything should happen at all, nobody will ever have suffered the consequences they had suffered," Trump said.
"It's not fair when the burden is all on us, the United States," he said, as he defended his decision to withdraw troops from Syria and let regional countries, Turkey in particular, to complete the work of finishing the remnants of the ISIS terror group and Saudi Arabia to invest in development of the war-ravaged country.
In his interaction with reporters, Trump described how he gave "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.
"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 too. Because we are in their region.
They should be sharing the burden of costs and they're not," the US President said.
Last week, Trump surprised the world when he suddenly announced that the US was pulling out its troops from Syria.
The US currently has some 2,000 troops in Syria, which are now gradually headed home. US Defence Secretary James Mattis resigned in protest.
Trump has argued that the US now no longer needs to be present in Syria as the ISIS terror group has been defeated.
"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.
"In Syria, Erdogan said he wants to knock out ISIS, whatever's left, the remnants of ISIS.
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. We are spread out all over the world. We are in countries most people haven't even heard about. Frankly, it's ridiculous," Trump added.
The US has kept a sustained military presence in Iraq since the 2003 invasion launched by former President George W Bush.
Trump had come under intense criticism for not visiting US troops fighting overseas, even though he speaks frequently about his support for the military.
Before heading to Florida for Thanksgiving, Trump vowed he would visit troops, but did not specify a date or specific location. "I'm going to a war zone," he had said.