WASHINGTON, Aug. 15 -- Following a report from the New York Times on Sunday, the U.S. Democratic Party is now questioning if Republican presidential candidate Donald Trump is receiving money from pro-Russian groups.

According to the report, Ukraine's anti-corruption agency has found a ledger of the former Ukrainian government under pro-Russian President Viktor Yanukovych that included a 12.7-million-U.S.-dollar payment to Trump's campaign manager Paul Manafort.

But the agency has yet to determine whether Manafort has received the money.

The report also alleged that Manafort advised the Yanukovych government until it was overthrown by protests in 2014.

Citing the report, Hillary Clinton's campaign urged Manafort to disclose any links with the pro-Russian politician.

Manafort has denied pocketing the record cash. "I have never received a single 'off-the-books cash payment' as falsely 'reported' by the New York Times," Manafort said.