WASHINGTON (Reuters) - The United States has started bringing home troops from Syria as it moves to a new phase in the campaign against Islamic State, the White House said on Wednesday, claiming that the militant Islamist group’s “territorial caliphate” has been defeated.

“These victories over ISIS in Syria do not signal the end of the Global Coalition or its campaign. We have started returning United States troops home as we transition to the next phase of this campaign,” White House spokeswoman Sarah Sanders said in a statement.

Earlier on Wednesday, U.S. officials said the United States was considering a total withdrawal of U.S. forces from Syria as it winds up its campaign to retake all of the territory once held by Islamic State.

President Donald Trump declared victory against the militant group in Syria on Wednesday and hinted that a withdrawal could be imminent. “We have defeated ISIS in Syria, my only reason for being there during the Trump Presidency,” he said in a tweet, referring to Islamic State by an acronym.

Sanders echoed Trump’s declaration of victory over Islamic States. “Five years ago, ISIS was a very powerful and dangerous force in the Middle East, and now the United States has defeated the territorial caliphate,” she said.

A decision to withdraw the last of about 2,000 troops, if confirmed, would upend assumptions about a longer-term U.S. military presence in Syria, which U.S. Defense Secretary Jim Mattis and other senior U.S. officials have advocated to help ensure Islamic State cannot re-emerge.