Donald Trump's campaign chairman, Paul Manafort, has been named in a corruption investigation in Ukraine, where officials are trying to track illegal payments from a pro-Russian political party that once hired the Washington-based political consultant.

More than US$12 million in undisclosed cash payments were earmarked for Manafort by the party of Ukraine's former President, Viktor Yanukovych, who fled Ukraine for Moscow after being ousted in 2014, according to a statement by the National Anti-Corruption Bureau of Ukraine.

Manafort denied receiving any improper payments, saying in a prepared statement today that he has "never received a single 'off-the-books' cash payment".

"The suggestion that I accepted cash payments is unfounded, silly and nonsensical," Manafort said, adding that he never worked for the governments of Ukraine or Russia and that he stopped working in Ukraine after the October 2014 elections there.


"The simplest answer is the truth: I am a campaign professional," Manafort said in the statement. "It is well-known that I do work in the United States and have done work on overseas campaigns as well."

Manafort's role in the Ukraine inquiry, first reported by the New York Times, serves as a reminder that Trump, who has faced bipartisan criticism for unusually friendly views toward Russia and has sought real estate deals there, has relied on advisers with personal and financial ties to Moscow and the former Soviet Union.

Retired Lieutenant-General Michael Flynn, a former military officer whom Trump briefly considered naming as a running-mate, was paid to give a speech and attend a lavish party with Russian President Vladimir Putin honouring the Kremlin-funded media company, RT Television.

Another foreign policy adviser, Carter Page, has said he holds stock in Gazprom, the Russian energy firm, whose stock price has stumbled since the imposition of US sanctions following the Russian invasion of Crimea.

Manafort's Ukraine connections drew scrutiny during last month's Republican convention, when the party platform committee weakened language that would have called for US military support of Ukraine. Manafort has denied that the campaign played a role, but committee members told the Washington Post that Trump aides were involved.

A spokeswoman for the anti-corruption bureau, Darya Manzhura, said today that payments to Manafort were listed in a ledger recovered from the headquarters of Yanukovych's political party, the Party of Regions. Investigators did not specify the reason the money was designated for Manafort from 2007 to 2012.

The ledger includes more than 20,000 line items, and investigators are sifting through the names as they investigate whether government resources were misused during the period Yanukovych was in power.

The anti-corruption bureau cannot make indictments but must pass on any evidence to prosecutors, who can decide whether to file charges. Manzhura said that processing the list will take a long time, as will matching signatures to individuals and proving that money actually changed hands.

For investigators, she said, Manafort is not the priority.

"He's not a Ukrainian government official, so taking into account the role and tasks of the National Anti-Corruption Bureau, Paul Manafort is not the number-one priority to investigate on this list," Manzhura said.

1 Paul Manafort, 67, is a longtime lobbyist, Republican strategist and global dealmaker.
2 He was hired by Donald Trump earlier this year and has gained enormous clout inside the campaign.
3 Manafort's lobbying clientele included two corrupt dictators, Mobutu Sese Seko of Zaire and Ferdinand Marcos of the Philippines, both of whom stole billions of dollars from their countries.
4 Manafort has parlayed political relationships around the world into an array of intricate financial transactions with billionaire oligarchs and other controversial investors that have at times spurred legal disputes.
5 In one case, Manafort tried unsuccessfully to build a luxury high-rise in Manhattan with money from Dmitry Firtash, a billionaire backer of Ukraine's former President, Viktor Yanukovych.