KIEV (WASHINGTON POST) - A Ukrainian lawmaker released new financial documents on Tuesday (March 22) allegedly showing that a former campaign chairman for US President Donald Trump laundered payments from the party of a disgraced ex-leader of Ukraine using offshore accounts in Belize and Kyrgyzstan.

The new documents, if legitimate, stem from business ties between the Trump aide Paul Manafort and the party of former Ukrainian president Viktor Yanukovych, who enjoyed Moscow's backing while he was in power.

Yanukovych has been in hiding in Russia since being overthrown by pro-Western protesters in 2014, and is wanted in Ukraine on corruption charges.

The latest documents were released just hours after the House Intelligence Committee questioned FBI Director James B. Comey about possible coordination between the Trump campaign and Moscow. The hearing also touched on Mr Manafort's work for Yanukovych's party in Ukraine.

Mr Comey declined to say whether the FBI is coordinating with Ukraine on an investigation of the alleged payments to Mr Manafort.

Mr Manafort, who worked for Yanukovych's Party of Regions for nearly a decade, resigned from Mr Trump's campaign in August after his name surfaced in connection with secret payments totaling US$12.7 million (S$17.7 million) by Yanukovych's party.

Mr Manafort has denied receiving those, listed in the party's "black ledger".

Mr Serhiy Leshchenko, a lawmaker and journalist, released a copy of an invoice on letterhead from Mr Manafort's consulting company, based in Alexandria, Virginia, dated Oct 14, 2009, to a Belize-based company for US$750,000 for the sale of 501 computers.

On the same day, Mr Manafort's name is listed next to a US$750,000 entry in the "black ledger", which was considered a party slush fund. The list was found at the party headquarters in the turmoil after Ukraine's 2014 revolution. The ledger entries about Mr Manafort were released by the National Anti-Corruption Bureau of Ukraine, a government law enforcement agency, last August.

Mr Leshchenko alleges that Mr Manafort falsified an invoice to the Belize company to legitimise the US$750,000 payment to himself.

"I have found during this investigation that (Manafort) used offshore jurisdictions and falsified invoices to get money from the corrupt Ukrainian leader," Mr Leshchenko said during a news conference in downtown Kiev, where he provided a copy of the invoice to journalists.

He said he received the invoices and other documents in January from the new tenants of Mr Manafort's former offices in downtown Kiev. The documents were left behind in a safe, he said, adding that Mr Manafort's signature and his company seal were proof that the documents were authentic.

Mr Leshchenko said he was not aware of any formal Ukrainian investigation of the documents. He declined to comment on whether he had discussed the documents with US law enforcement agencies.

Mr Nazar Kholodnytskyi, a deputy prosecutor general of Ukraine whose department specialises in corruption cases, said in an interview on Tuesday that the documents hadn't been confirmed by law enforcement or, to his knowledge, submitted for examination. There is an ongoing investigation into the black ledgers, he said, but Mr Manafort was not a target of that investigation.

Mr Manafort has previously accused Mr Leshchenko of blackmailing him by threatening to release harmful information about his financial relationship with Mr Yanukovych. That correspondence between Mr Leshchenko and Mr Manafort's daughter was released in February as the result of a purported cyberhack. Mr Leshchenko has called the exchange a forgery.

Mr Manafort was involved in crafting the political strategy that brought Mr Yanukovych to power after a crushing defeat in the 2004 elections. Mr Yanukovych's party has been accused of ties to Russian President Vladimir Putin, particularly through wealthy oligarchs from the country's east with interests in both Russia and Ukraine.