A major federal corruption investigation into Mayor Eric Adams’s fund-raising is examining whether his campaign conspired with members of the Turkish government to receive illegal donations.

Mr. Adams, a Democrat in his second year in office, has longstanding ties to Turkey. The mayor has said that he met the Turkish president, Recep Tayyip Erdogan, when he was Brooklyn borough president, and that he has visited the country at least six times.

Now federal prosecutors and the F.B.I. are investigating Mr. Adams’s connections to Turkey, including whether he pressured city officials to sign off on the Turkish government’s new consulate building in Manhattan and the role of a Brooklyn building company owned by Turkish immigrants that organized a fund-raising event for him.

Federal authorities raided the home of Mr. Adams’s chief fund-raiser on Nov. 2, and then seized at least two cellphones and an iPad from Mr. Adams himself. Mr. Adams has defended his links to Turkey, arguing that they were part of his outreach to immigrant communities that have not always received attention from City Hall.

Here’s what we know about the mayor’s Turkey connections.

Thousands of dollars from donors linked to Turkey

Mr. Adams has received campaign donations from Turkish immigrants and from people linked to prominent Turkish groups aligned with Mr. Erdogan, a conservative leader who took office in 2014.