New York City Mayor Eric Adams has been indicted on at least one federal criminal charge, multiple sources familiar with the matter tell CNN.

The New York Times was first to report the news of the indictment.

The indictment follows a monthslong federal investigation into campaign fundraising violations and foreign influence. The charges he is facing are not publicly known at this time.

Adams has previously denied any wrongdoing, and he has frequently repeated that he told members of his campaign and administration to follow the law.

“I always knew that If I stood my ground for New Yorkers that I would be a target—and a target I became. If I am charged, I am innocent and I will fight this with every ounce of my strength and spirit,” Adams said responding to the news on Wednesday night.

The mayor is expected to have several days to turn himself in, according to sources familiar with the case.

Adams was at Gracie Mansion, the mayor’s official residence, when word of the indictment broke. He’s said to be undeterred and resolute in his demeanor, according to a source familiar with the situation.

CNN has sought comment from lawyers for the mayor and City Hall. The US attorney’s office for the Southern District of New York has declined to comment.

The indictment is a dramatic fall from grace for the mayor of America’s largest city and a stunning accusation against one of the nation’s most high-profile offices.

Adams, a former NYPD captain, took office in January 2022 and presented himself as the new face of the Democratic Party, promising a tough-on-crime approach and a commitment to revitalizing the city after the COVID-19 pandemic. Yet he has struggled to resolve the city’s key challenges, such as the migrant crisis and concerns about subway safety, and has faced criticism for his late-night partying and clashes over city spending, particularly on education.

Now, nearly three years into his first term, Adams is facing at least one federal charge that jeopardizes his ability to remain in office and threaten the future of his political career.

When asked on Tuesday if he was considering resigning, Adams said, “I’m stepping up, not stepping down.”

The mayor’s legal troubles escalated in September when top members of his staff at City Hall, including two deputy mayors, a senior adviser, and the schools chancellor, received search warrants and had their phones seized by federal investigators.

Edward Caban, the former New York Police Department commissioner, also had his phone seized as part of a separate federal investigation and was forced to resign. Days later, Lisa Zornberg, City Hall’s top lawyer and one of Adams’ staunchest defenders, abruptly resigned. In a brief two-sentence resignation letter, Zornberg stated that she had concluded she could “no longer serve effectively” in her position. A week later, Schools Chancellor David Banks announced he would retire at the end of the year, stepping down from his position leading the nation’s largest public school system just days after his home was searched by federal investigators who seized his cell phones during the execution of a federal search warrant.

The first sign of trouble for Adams came nearly a year ago when federal investigators zeroed in on his chief campaign fundraiser, Brianna Suggs, and executed a search warrant at her home, multiple law enforcement officials previously told CNN. Suggs has not been charged with any crimes.

Investigators from the FBI’s public corruption squad seized phones, computers, tablets, and files from Suggs, according to sources. Agents also executed numerous search warrants at other homes and businesses throughout the New York area in connection with the investigation, officials said.

One of the companies searched in November 2023 was KSK Construction Group in Brooklyn, law enforcement officials said. The construction and development company has built apartments and condos throughout the city.

A CNN review of campaign finance records identified at least 11 employees at KSK Construction Group who donated a total of $13,950, with individual contributions ranging from $1,200 to $1,500, all on the same day, to Adams’ 2021 mayoral campaign. CNN has reached out to the donors for comment.

CNN has also reached out to Erden Arkan, who is listed as the owner of KSK Construction Group, and also listed as a donor to the Adams campaign. New York City campaign finance records show Arkan donated $1,500.

As part of their investigation, FBI agents seized Adams’ cell phones days after the raid on Suggs’ home.

After Adams gave a speech in Manhattan, FBI agents “walked right up to him,” asked his NYPD security detail to step aside, and then climbed into Adams’ city-issued SUV, sources previously told CNN. It was there that agents presented him with a warrant to seize his electronic devices, the sources said.

The seizure marked a dramatic escalation of the federal probe into whether foreign money was funneled to his campaign, bringing the investigation directly to the Democratic mayor.

Adams has maintained his innocence throughout and insisted that he and his staff have followed the law, despite the mounting investigation.

The mayor has touted his ties to the city’s Turkish American community and said he had visited the country at least six or seven times.

Adams traveled to Turkey at least twice as Brooklyn borough president. The Turkish Consulate paid for an August 2015 trip during which he signed a sister city agreement with Istanbul’s Üsküdar district.

Adams is not required to step down in light of the charges, although the political pressure may become untenable. If he were to resign, the job of America’s most high-profile mayor would go to the city’s public advocate, Jumaane Williams until a special election occurred.