Mayor Bill de Blasio insisted Sunday that he knows nothing about the feds’ investigation into his fundraising activities — two days after promising to return shady donations just as news of the probe broke.

“I haven’t heard anything about any investigation,” the mayor said on NBC’s “Meet the Press” Sunday morning. “There haven’t been any questions posed to me or my team.”

He refused to address the investigation further at a public appearance in the afternoon, saying he has “no evidence” the feds were putting his fundraising under a microscope.

“We’ve gotten no indication of that, and until we have something specific to respond to, there’s nothing to respond to,” he said.

De Blasio said Friday that he would return donations from one of the businessmen at the center of the FBI’s widening investigation into NYPD corruption.

The announcement was made amid revelations that US Attorney Preet Bharara, according to sources, is looking at how the mayor solicits campaign cash from members of the real estate industry.

The Post revealed last week that de Blasio received sizable donations from Jona Rechnitz, owner of a real estate investment company who is suspected of being part of an alleged gifts-for-favors scheme in the NYPD.

Jeremy Reichberg, another target of the probe, held a fundraiser at his million-dollar-plus home in Borough Park for de Blasio’s nonprofit, the Campaign for One New York. The mayor attended.

De Blasio tried to downplay his ties to the men, who served on his inaugural committee in 2013.

“It’s not a particularly close relationship,’’ he said. “I met them first around the time of the general election. I hadn’t known them previously, really haven’t seen them in the last year or more. They supported the effort.”

Rechnitz shelled out $50,000 to the Campaign for One New York, which has announced it will shut down. He and his wife gave another $9,900, the maximum amount, to the mayor’s 2013 campaign.

But de Blasio stood by his former campaign finance director, Ross Offinger, whose fundraising tactics, sources say, are being probed by the feds.

“I think [Offinger] has handled everything with integrity and everything appropriately,” he said.

De Blasio promised that his campaign had followed the law in raising cash.

“We are very, very scrupulous about that,” he told “Meet the Press.” “Everything we’ve done is appropriate and carefully, carefully done with many, many lawyers, I assure you.”

He claimed he decided to return the two men’s donations after four high-ranking NYPD officers were disciplined last week.

“What we’ve seen so far, that Internal Affairs has come to the conclusion that something was done wrong, of course that’s troubling,” he said.

“We have to go through the whole due process effort to find what they did and what they didn’t in terms of the Police Department and then we can pass fuller judgment.”