Mayor Eric Adams of New York City, a former police captain who ran on a law-and-order platform but whose tenure has been consumed by accusations of corruption, spent years accepting free airline tickets, lavish overseas accommodations and illegal campaign donations from Turkey, federal prosecutors said on Thursday.

In return for the gifts and donations, Mr. Adams used his influence as Brooklyn borough president and later as mayor to assist Turkish officials with issues they were facing in the city, prosecutors said — most notably in obtaining safety clearances from the Fire Department for a new high-rise Turkish consulate building.

Thursday’s dramatic events began with the startling sight of federal agents marching into Gracie Mansion, the official residence of New York mayors since World War II. And shortly before noon, prosecutors unveiled the first federal indictment in the city’s modern history of a sitting mayor.

Mr. Adams was charged with five counts, including bribery, fraud and soliciting illegal foreign campaign donations. He was ordered to appear in Federal District Court in Manhattan on Friday for an arraignment before a magistrate judge.

“This was a multiyear scheme to buy favor with a single New York City politician on the rise: Eric Adams,” Damian Williams, the U.S. attorney for the Southern District of New York, said at a news conference.