Mayor de Blasio will be questioned by federal prosecutors Friday morning as part of the wide-ranging investigation into his campaign fundraising, sources told The Post.

The long-anticipated sit-down with prosecutors from Manhattan US Attorney Preet Bharara’s office will take place at the Midtown offices of the mayor’s lawyer, Barry H. Berke of Kramer Levin Naftalis & Frankel, sources said.

The feds have been probing whether de Blasio and his aids traded favors in exchange for donations to his 2013 campaign or to his shuttered nonprofit, the Campaign for One New York.

Recently, investigators have been zeroing in on de Blasio’s relationship with rabbi and political fundraiser Moishe Indig, a leader in Williamsburg’s Hasidic community who hosted a fundraising event for the mayor in Oct. 2013, The New York Times reported.

The feds seized one of his cell phones in late December, and have been probing whether de Blasio may have given favors to Indig — who landed on de Blasio’s “Worst Landlords” list when he was still public advocate — for his support.

Investigators have also been probing his relationship with restaurant owner Harendra Singh, who is facing bribery and tax-evasion charges and has been cooperating with the feds.

Meanwhile, grand juries have been hearing evidence related to separate state and federal inquiries into the de Blasio administrations fundraising practices.

De Blasio’s spokesman Eric Phillips declined to comment on the mayor’s meeting with the feds.