NEW YORK (Reuters) - New York City Mayor Bill de Blasio met with federal prosecutors on Friday as part of their lengthy investigation into whether people involved in fundraising for his election campaign broke corruption laws, according to news reports.

FILE PHOTO -- New York City Mayor Bill de Blasio presents the Fiscal Year 2018 Preliminary Budget at New York City Hall in New York, U.S., January 24, 2017. REUTERS/Sam Hodgson/The New York Times/Pool/File Photo

De Blasio, a Democrat who faces reelection in November, has repeatedly said he and his campaign staff have done nothing wrong and that he was cooperating with prosecutors from the U.S. attorney’s office in Manhattan in their yearlong criminal investigation.

“We did everything right,” he said in a television interview last month. “My team did everything right.”

Prosecutors and agents from the Federal Bureau of Investigation questioned him on multiple topics, according to the New York Times.

The meeting took place at his lawyers’ office in Manhattan, and his black sport-utility vehicle was seen departing from the office garage about five hours after it arrived. News photographers briefly gave chase, but de Blasio did not emerge from the vehicle to speak with waiting reporters.

A spokesman for the mayor did not respond to questions on Friday.

Prosecutors from the Manhattan U.S. attorney’s public corruption unit are looking at whether people who helped raise money for de Blasio’s 2013 election campaign and a non-profit organization that his advisers operated received favorable treatment from the mayor or his aides at City Hall, according to news reports.

A spokesman for the U.S. attorney’s office, which typically does not discuss ongoing investigations, declined to comment.

After the meeting, the mayor, who had no public events planned for the day, headed to the airport to fly to Atlanta for a meeting of the Democratic National Committee, according to his published schedule.

Last month, de Blasio confirmed he was interviewed by state-level prosecutors from the Manhattan district attorney’s office in a separate investigation into his fundraising practices. He is no longer a target of that inquiry, although some of his aides may still be under scrutiny, according to the New York Times.

The private law firms defending the mayor and other officials are costing the city more than $11.6 million, the paper reported.