European Union lawyers are examining whether parts of a deal with the United States on tracking terrorist finances are legal amid calls to renegotiate the entire agreement.

European Parliament civil liberties committee chairman Claude Moraes said Thursday that there is "a legal issue here, about the legality and validity" of parts of the Terrorist Finance Tracking Program.

The problem relates to EU oversight of the conditions under which the U.S. Treasury can access the SWIFT system overseeing international bank transfers.

Ombudswoman Emily O'Reilly said the U.S. Treasury is denying her access to a report on how that agreement is being handled. O'Reilly said that "for the first time in its 20-year history, the European ombudsman was denied its right under statute." European parliament lawyers are now looking into the deal.