File Photo: The U.S. flag flutters on a military vehicle in Manbej countryside, Syria May 12, 2018. (Xinhua/REUTERS)

WASHINGTON, Dec. 30 (Xinhua) -- U.S. Republican Senator Lindsey Graham indicated on Sunday that President Donald Trump has agreed to slow down the withdrawal of U.S. forces from Syria.

"I think we're slowing things down in a smart way," Graham told reporters after a lunch with Trump.

"I think we're in a pause situation where we are reevaluating what's the best way to achieve the president's objective of having people pay more and do more," the Republican lawmaker said.

"The president understands the need to finish the job," Graham said. "We talked about Syria. He told me some things I didn't know that made me feel a lot better about where we're headed in Syria. We still have some differences, but I will tell you that the president is thinking long and hard about Syria -- how to withdraw our forces but at the same time achieve our national security interests."

"I think the president is committed to making sure when we leave Syria that IS (Islamic State) is completely defeated," he said when asked if Trump has agreed to slow down the withdrawal. "The president is reconsidering how we would do this."

On future plans, the congressional veteran noted that "I think the president has come up with a plan with his generals that makes sense to me," without giving further details.

Graham has been among the vocal critics of Trump's earlier announced withdrawal of U.S. troops from the Middle East country.

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 IS.

Trump tweeted one day later that Defense Secretary James Mattis will retire at the end of February, but changed his decision by the end of that week 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.

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

In a surprise visit to U.S. troops in Iraq later in December after his controversial decisions, Trump promised a "strong deliberate and orderly withdrawal" from Syria.

"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," he said.

On Friday, the Pentagon tweeted that "the next phase of U.S. support to the #Coalition's operation in #Syria is a deliberate, well thought-out, mutually supportive, and controlled withdrawal of forces while taking all measures possible to ensure our troops' safety and protection."

The U.S. media reported that one of the withdrawal options is to manage a 120-day pullout period.

Also on Friday, Trump's National Security Adviser John Bolton tweeted that he is "looking forward to visiting Israel & Turkey in January."

"We will discuss our continued work confronting security challenges facing allies & partners in the region, including the next phase of the fight against ISIS (IS), as the U.S. begins to bring troops home from Syria," he added.