The U.S. has started withdrawing its troops from Syria, according to a statement by the White House on Wednesday.

"We have started returning U.S. troops home as we transition to the next phase of this campaign," Press Secretary Sarah Sanders announced.

Earlier, President Trump said on Twitter that the U.S. has defeated ISIL in Syria, which he said was the "only reason for [the military] being there during the Trump presidency."

WH: President Trump is honoring promise

In April, Trump announced that over the last year, nearly 100 percent of the territory once controlled by ISIL in Syria and Iraq has been liberated. He also said, "as other nations step up their contributions, we look forward to the day when we can bring our warriors home."

Concerning the withdrawal of troops from Syria, the White House said the president is honoring his promise.

The Global Coalition against ISIL will not end, the statement mentioned, adding the U.S. and its allies stand ready to re-engage at all levels to defend American interests whenever necessary.

Taking back territory doesn't mean defeating

U.S. officials have warned that taking back the group's territory would not be the same as defeating it, Reuters reported.

Some of Trump's Republican allies in Congress railed against the pullout decision. U.S. Senator Lindsey Graham said a withdrawal would have "devastating consequences" for the U.S. in the region and throughout the world.

The withdrawal decision also raised eyebrows abroad, reports said.

A British defense minister said he strongly disagreed with Trump that ISIL had been defeated in Syria. Israeli Prime Minister Benjamin Netanyahu said Israel would study the decision and would ensure its own security.

France will maintain its participation in the coalition fighting ISIL in Syria, a government minister said Thursday.

"For now, of course, we remain in Syria," France's European Affairs Minister Nathalie Loiseau said on CNews television, adding "the fight against terrorism is not over."

German Foreign Minister Heiko Maas said Thursday that U.S. withdrawal could endanger the battle against ISIL and jeopardize achievements on this front. 

In Russia, TASS news agency quoted the Foreign Ministry as saying withdrawing U.S. troops from Syria created prospects for a political settlement.

Currently, about 2,000 U.S. troops are in Syria.

China calls for 'Syrian-led inclusive process'

At a regular press briefing on Thursday, Chinese Foreign Ministry spokeswoman Hua Chunying said Beijing always respects Syria's sovereignty and territorial integrity, stressing that the future of Syria should be decided by the Syrian people.

With terrorist groups seriously weakened in Syria, efforts to resolve the Syria issue have entered a "key stage," Hua said in response to the withdrawal of American troops from Syria.

"We hope all sides involved can make joint efforts to create conditions for an early start of a Syrian-led inclusive process, and work towards the resolution of the Syria issue at an early date," she added. "This is in line with common interests of all parties in the international community."

SDF: U.S. withdrawal from Syria will spark ISIL revival

The U.S.-backed Syrian Democratic Forces (SDF) said on Thursday the withdrawal from Syria will allow an ISIL revival and threaten the battle in eastern Syria.

The Kurdish-led force said pulling U.S. troops and officials out of its region would have "dangerous implications" on international stability.

This would also "create a political and military vacuum in the area, leaving its people between the claws of hostile parties," the statement said.

 "It will have a negative impact on the counterterrorism campaign". 

(With inputs from agencies)