The Pentagon said Wednesday it had started the process of returning U.S. troops from Syria as the United States began to transition into the next phase of the campaign, Reuters reported.

“The Coalition has liberated the ISIS-held territory, but the campaign against ISIS is not over,” Pentagon spokeswoman Dana White said in a statement, using an acronym for Islamic State.

“We have started the process of returning U.S. troops home from Syria as we transition to the next phase of the campaign,” she said.

“For force protection and operational security reasons we will not provide further details. We will continue working with our partners and allies to defeat ISIS wherever it operates.”