Trump's remarks follow comments last week when he vowed US forces would shortly quit Syria, a position at odds with establishment doctrine that a premature pullout from the war-torn nation would have far-reaching negative consequences.

"Our primary mission in terms of Syria was getting rid of ISIS," Trump said, using an acronym for the Islamic State group.

"We've almost completed that task. And we'll be making a decision very quickly in coordination with others in the area as to what we'll do."

The president added: "I want to get out, I want to bring our troops back home. I want to start rebuilding our nation."

But even as Trump was speaking at a news conference with Baltic leaders, the top commander for the war against IS signaled different views.

General Joe Votel, who leads the military's Central Command, suggested the US should play a long-term role in Syria in terms of stabilizing the areas that once had been freed from IS occupation.

"The hard part I think is in front of us and that is stabilizing these areas, consolidating our gains, getting people back into their homes, addressing the long term issues of reconstruction and other things that will have to be done," Votel said.

"Of course there is a military role in this, certainly in the stabilization phase," he added at at the US Institute of Peace in Washington.

And Brett McGurk, the US envoy to the coalition against IS, said the fight against the jihadists was not over.

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Officials say 98 percent of the vast areas of land IS once held in Syria and Iraq have been liberated, but the group maintains a presence along the Euphrates River Valley in eastern Syria and the military is wary of the fighters mounting a long-term insurgency.

"We are ahead of where we thought we would be at this time, but we are not finished and we have to work through some very difficult issues as we speak," McGurk said.

Trump said he would consult with allies and suggested that Saudi Arabia might pay the bill for US troops being there.

"Saudi Arabia is very interested in our decision. And I said, well, you know, you want us to stay maybe you'll have to pay," he said.

In another sign of Trump's waning interest in Syria, The Wall Street Journal has reported that he had placed on hold $200 million in US funding to help stabilize areas of eastern Syria recaptured from IS.

"The president has been very clear to us that everything we're doing has to constantly be reviewed and looked at," McGurk said.

"On this $200 million, we're looking at where can it be spent most effectively."

Trump's apparent willingness to step away from the chaos of Syria runs counter to a new US strategy announced in January by then secretary of state Rex Tillerson -- who has since been sacked.

Tillerson argued US forces must remain engaged in Syria to prevent IS and Al-Qaeda from returning and to deny Iran a chance to "further strengthen its position in Syria."