NEW YORK — Hillary Clinton’s campaign is questioning the ties a top political aide to Donald Trump had to a pro-Kremlin political party in Ukraine, claiming it is further evidence of the Republican nominee’s cozy relationship with Russia.
The New York Times reported that handwritten ledgers found in Ukraine show $12.7 million in undisclosed payments to Paul Manafort, Trump’s campaign manager, from the pro-Russia party founded by the country’s former president Viktor Yanukovych.
Ukrainian investigators are looking into whether the money was part of an illegal off-the-book system that may have also made payments to election officials, the Times reported in Monday’s editions.
Clinton campaign manager Robby Mook said in a statement that Trump has a responsibility to disclose all ties that Manafort and any other campaign employees have to Russian or pro-Kremlin entities, “including whether any of Trump’s employees or advisers are currently representing and or being paid by them.’’
Manafort, who has had several international clients including Philippine dictator Ferdinand Marcos, denied any wrongdoing.
‘‘The simplest answer is the truth: I am a campaign professional,’’ said Manafort in a statement released Monday. ‘‘I have never received a single ‘off-the-books cash payment’ as falsely reported by The New York Times, nor have I ever done work for the governments of Ukraine or Russia.’’
He added that his five-year stint as doing work as a political consultant in Ukraine ended after that country’s elections in 2014.
Svitlana Olifira, a spokeswoman for Ukraine’s National Anti-Corruption Bureau, confirmed that the documents were recovered, but cautioned that the investigation was in its early stages.
‘‘It’s a bit early to say if we really will have a separate investigation related to the name of Manafort, since we are still studying [the documents],’’ said Olifira. ‘‘I want to stress that his name appears there not just once, but we cannot say if he physically received the money assigned to him, as there are other signatures near his name.’’
Trump’s relationship with Russia has drawn scrutiny in the campaign, most recently when he encouraged hackers from that country to find Clinton’s missing e-mails, an apparent invitation for a foreign power to intervene in a US election. Trump also has frequently praised Russian President Vladimir Putin.
Ukraine criminal prosecutors are also investigating a group of offshore shell companies that helped members of Yanukovych’s inner circle finance their lavish lifestyles, including a palatial presidential residence with a private zoo, golf course, and tennis court, the Times reported.
Among the hundreds of murky transactions these companies engaged in was an $18 million deal to sell Ukrainian cable television assets to a partnership put together by Manafort and a Russian oligarch, Oleg Deripaska, a close ally of Putin.
Anticorruption officials in Ukraine say the payments earmarked for Manafort, previously unreported, are a focus of their investigation, though they have yet to determine if he actually received the cash. While Manafort is not a target in the separate inquiry of offshore activities, prosecutors say he must have realized the implications of his financial dealings.
Manafort’s lawyer, Richard A. Hibey, told the Times that Manafort had not received “any such cash payments” described by the anticorruption officials.
Hibey also disputed a suggestion that Manafort might have countenanced corruption or been involved with people who took part in illegal activities.
“These are suspicions, and probably heavily politically tinged ones,” said Hibey, a member of the Washington law firm Miller & Chevalier. “It is difficult to respect any kind of allegation of the sort being made here to smear someone when there is no proof and we deny there ever could be such proof.”
The developments in Ukraine underscore the risky nature of the international consulting that has been a staple of Manafort’s business since the 1980s, when he went to work for the Philippine dictator Ferdinand Marcos. Before joining Trump’s campaign this spring, Manafort’s most prominent recent client was Yanukovych, who — like Marcos — was deposed in a popular uprising.
Before he fled to Russia two years ago, Yanukovych and his Party of Regions relied heavily on the advice of Manafort and his firm, who helped them win several elections. During that period, Manafort never registered as a foreign agent with the US Justice Department — as required of those seeking to influence US policy on behalf of foreign clients — although one of his subcontractors did.