Sen. Bob Menendez is under criminal federal investigation: report

New Jersey Democratic Senator Bob Menendez is under criminal federal investigation, ABC News reports.

As ABC News points out, it's not clear what the nature of the investigation is.

"Senator Menendez is aware of an investigation that was reported on today, however he does not know the scope of the investigation. As always, should any official inquiries be made, the Senator is available to provide any assistance that is requested of him or his office," Menendez adviser Michael Soliman said in a statement to ABC News.

Menendez, who chairs the powerful Senate Foreign Relations Committee, was previously indicted on corruption charges in 2015 in regards to his relationship with a Florida eye doctor, Salomon Melgen, where he was accused of accepting close to $1 million worth of campaign contributions and lavish gifts. He pleaded not guilty and the trial ended with a hung jury.