The United States’ strategy in Syria is to wage the ground campaign against the Islamic State through local forces in order to maintain a small American footprint. But even that requires the deployment of American advisers, plus artillery, satellite-guided rockets, Apache attack helicopters and Army Rangers — some 1,000 troops in all. The American presence comes as Iran and the Shiite militias it backs, as well as the Syrian government and Russia, are maneuvering to control territory in eastern Syria after Raqqa is taken.

The visit to Tabqa on Thursday was a first opportunity for Mr. McGurk, a small group of senior coalition officials and the Western news media to get a look at the newly liberated city, still struggling to recover from the physical and psychological scars of nearly three years of harsh control by the militants.

“Basically, what you’ve got here is hundreds, if not thousands, of bodies in the rubble, which is causing a lot of flies, the flies are biting kids, the kids are getting infected,” said Al Dwyer, a senior official with the United States Agency for International Development, as American Special Operations forces drove to Tabqa in armored S.U.V.s. “Lot of rats. Smells. This is keeping people from coming back in.”

The Tabqa operation was proposed in mid-March to Lt. Gen. Stephen Townsend, the commander of the American-led task force that is battling the Islamic State, by the top commander of the Syrian Democratic Forces, the combination of Syrian Kurds and Arab fighters who would provide the ground troops for the battle. It was approved without a single White House meeting.

Just one week later, hundreds of Arab and Kurdish fighters, including many who had never flown before, were airlifted on American helicopters and Osprey planes to the southern banks of Lake Assad, across from Tabqa. Barges ferried their vehicles across the azure water while another group of Syrian fighters to the east hopped from island to island as they zipped along the Euphrates on American fast boats.