The funds were owed by shell companies linked to Manafort's business ventures in Ukraine, where he worked for the Party of Regions, a Ukrainian political faction, the Times said, citing financial records.
The party, which boasted close ties to Moscow, was in power under former president Viktor Yanukovych.
This isn't the first time Manafort's debts have been publicized. In 2015, Russian oligarch Oleg Deripaska claimed he was owed $19 million by Manafort and his partners regarding a Ukrainian business investment.
A spokesman for Manafort, Jason Maloni, told The New York Times that "Manafort is not indebted to Deripaska or the Party of Regions, nor was he at the time he began working for the Trump campaign."