New York City Mayor Eric Adams has been issued a federal grand jury subpoena as part of an investigation into corruption and illegal campaign donations, according to two sources familiar with the matter.

City Hall and Adams’ 2021 mayoral campaign committee also received a set of subpoenas, which were issued in July and cover a variety of materials including text messages, communications and other documents, one of the sources said.

The subpoenas are the latest development in the monthslong investigation into Adams and his campaign that has focused on possible public corruption and foreign influence.

Adams was not personally served, according to a source familiar. There’s no appearance and no deposition in this request. Letters were delivered to his attorneys and to City Hall’s counsel.

The subpoena to City Hall is an expansive request for information that pertains to the related issues under investigation, which includes links to Turkey and foreign travel, according to the source. Both the campaign and Adams are being asked to provide more details on items that initially raised red flags for investigators.

The New York Times was first to report on the new subpoenas.

Fabien Levy, the mayor’s chief spokesperson, repeated much of what the mayor has said since the investigation began – denying that Adams did anything wrong and highlighting his cooperation with the investigation.

“As a former member of law enforcement, the mayor has been clear over the last nine months that he will cooperate with any investigation underway. Nothing has changed,” Levy said. “He expects everyone to cooperate to swiftly bring this investigation to a close,” Levy said.

The FBI and the US Attorney’s Office for the Southern District of New York declined to comment.

It is not the first time Adams has been the target of federal investigators. Last year, FBI agents seized his cellphones and iPad pursuant to a court warrant.

CNN has previously reported the investigation into Adams is focused on campaign money, possible favors and foreign influence. The investigation has dragged on for several months and first became public after it was reported the FBI and investigators with the US Attorney’s Office for the Southern District of New York raided the home of Brianna Suggs, Adams’ chief fundraiser. Neither Adams nor Suggs have been accused of any wrongdoing.

Brendan McGuire, the mayor’s lawyer, who is also representing the campaign, said in a statement that Adams and the committee “continue to cooperate with the investigation and are in the process of responding to the recently issued subpoenas. We continue to look forward to a prompt and just resolution of this investigation.”

McGuire added that the mayor’s defense team has conducted an investigation into the areas they believe are being reviewed by the US Attorney’s office.

According to McGuire, their investigation so far has not identified “any evidence of illegal conduct by the Mayor. To the contrary, we have identified extensive evidence undermining the reported theories of federal prosecution as to the Mayor, which we have voluntarily shared with the US Attorney.”

Adams is currently more than halfway through his first term in office. At least three challengers have said they plan to run against Adams in the upcoming 2025 Democratic primary.

This story has been updated with additional reporting.