Washington, Aug 4 (IANS): US President Donald Trump called a New York City prosecutor's inquiry into his tax returns an attempt by Democrats to damage him in the election year.

"This is just a continuation of the witch hunt. It's Democrat stuff," Trump told reporters in the White House on Monday, adding that he knew nothing about the investigation, reports Xinhua news agency.

Earlier on Monday, a court filing suggested Manhattan District Attorney Cyrus Vance, a Democrat, is pursuing a criminal investigation of the Trump Organization.

In the court filing, lawyers for Vance said the attorney was justified in demanding the President's tax returns because of public reports of "extensive and protracted criminal conduct at the Trump Organization."

At the time when Vance issued a subpoena to Trump's accountants, "there were public allegations of possible criminal activity" at the president's company "dating back over a decade", the lawyers said.

The Supreme Court in July rejected Trump's claim that he was immune from grand jury investigations such as the one led by Vance.

Trump's attorneys have filed a new complaint following the 7-2 ruling, arguing that the subpoena is overly broad and amounts to presidential "harassment".

US District Judge Victor Marrero has scheduled arguments to be fully submitted by mid-August, according to local media reports.