On Thursday, President Trump suggested that the United States could pull its approximately 2,000 troops out of Syria “very soon.” The comments surprised Defense Department officials who have maintained that some kind of American presence in parts of Syria may be necessary to avoid recreating the conditions that led to the rise of the Islamic State — and also to avoid ceding influence in the country to Russia.

“Very soon, we’re coming out,” Mr. Trump said during a rally in Ohio. “We’re going to have 100 percent of the caliphate, as they call it — sometimes referred to as ‘land’ — taking it all back quickly, quickly.”

The suspension of funds for recovery efforts in Syria comes as the administration reassesses its role in the conflict there, a State Department official said on Friday. The freeze on funding was first reported by The Wall Street Journal.

“There will be meetings on this next week,” said the official, who spoke on the condition of anonymity because a policy review was continuing. “Obviously, we, State, hope that this decision is reversed.”

A National Security Council official explained the White House’s position: “In line with the president’s guidance, the Department of State continually re-evaluates appropriate assistance levels and how best they might be utilized, which they do on an ongoing basis.”

Secretary of State Rex W. Tillerson had committed the aid in February in Kuwait at a meeting of countries who have joined together to defeat the Islamic State.

Pentagon officials in the past few months have said repeatedly that a complete withdrawal of American troops could leave a void. On Tuesday, Defense Secretary Jim Mattis said that while American forces were no longer in “an offensive effort on the ground,” they continued to play a role. “We continue the operations in Syria,” he said.