Federal prosecutors and the F.B.I. are conducting a broad public corruption investigation into whether Mayor Eric Adams’s 2021 election campaign conspired with the Turkish government to receive illegal foreign donations, according to a search warrant obtained by The New York Times.

The investigation burst into public view on Thursday when federal agents conducted an early-morning raid at the Brooklyn home of the mayor’s chief fund-raiser, Brianna Suggs, a campaign consultant who is deeply entwined with efforts to advance the mayor’s agenda.

Investigators also sought to learn more about the potential involvement of a Brooklyn construction company with ties to Turkey, as well as a small university in Washington, D.C., that also has ties to the country and to Mr. Adams.

According to the search warrant, investigators were also focused on whether the mayor’s campaign kicked back benefits to the construction company’s officials and employees, and to Turkish officials.

The agents seized three iPhones and two laptop computers, along with papers and other evidence, including something agents identified as “manila folder labeled Eric Adams,” seven “contribution card binders” and other materials, according to the documents.

According to The New York Times, There was no indication that the investigation was targeting the mayor, and he is not accused of wrongdoing. Yet the raid apparently prompted him to abruptly cancel several meetings scheduled for Thursday morning in Washington, D.C., where he planned to speak with White House officials and members of Congress about the migrant crisis.

Instead, he hurriedly returned to New York “to deal with a matter,” a spokesman for the mayor said.

Appearing at a Día de Muertos celebration at Gracie Mansion on Thursday night, Adams defended his campaign, saying that he held it “to the highest ethical standards.”

He said he had not been contacted by any law enforcement officials, but pledged to cooperate in any inquiry. Adams said that he returned from Washington to be “on the ground” to “look at this inquiry” as it unfolded.

The warrant suggested that some of the foreign campaign contributions were made as part of a straw donor scheme, where donations are made in the names of people who did not actually give money. Investigators sought evidence to support potential charges that included the theft of federal funds and conspiracy to steal federal funds, wire fraud and wire fraud conspiracy, as well as campaign contributions by foreign nationals and conspiracy to make such contributions.

Adams has boasted of his ties to Turkey, most recently during a flag-raising he hosted for the country in Lower Manhattan last week. The mayor said that there were probably no other mayors in New York City history who had visited Turkey as frequently as he has.

The construction company was identified in the warrant, portions of which were obtained by The Times, as KSK Construction Group in Brooklyn. Individuals who listed their employer as KSK donated nearly $14,000 to Mr. Adams’s 2021 campaign, according to campaign finance records.

The search warrant sought financial records for Ms. Suggs and any entity controlled or associated with her; documents related to contributions to the mayor’s 2021 campaign; records of travel to Turkey by any employee, officer or associate of the campaign; and documents related to interactions between the campaign and the government of Turkey, “including persons acting at the behest of the Turkish government.”

Investigators specified documents relating to Bay Atlantic University, a tiny Turkish-owned institution that opened in Washington, D.C., in 2014. The following year, Adams visited one of the school’s sister universities in Istanbul, where he was given various certificates and was told that a scholarship would be created in his name.