Ukrainian authorities have released details of million dollar payments that US presidential campaign hopeful Donald Trump's former campaign chief allegedly received from Kiev's former Russian-backed leaders.

Key points: Paul Manafort worked for Moscow-backed Ukrainian president Victor Yanukovych

Paul Manafort worked for Moscow-backed Ukrainian president Victor Yanukovych Anti-corruption authorities in Ukraine said it could not be certain Mr Manafort received the money

Anti-corruption authorities in Ukraine said it could not be certain Mr Manafort received the money Reports in US media said Mr Manafort may have received $16.7 million

There are also claims that Paul Manafort lobbied in favour of a pro-Kremlin party, even after February's 2014 pro-EU revolt pulled Ukraine out of Russia's orbit.

Mr Manafort resigned on Friday from his position as chairman of the billionaire's campaign.

Both claims have distracted from the Republican nominee's bid for the White House that has seen Mr Trump trail his Democratic rival Hillary Clinton, and effectively demote Mr Manafort in an election team overhaul this week.

Mr Manafort served as a public relations adviser to Moscow-backed Ukrainian president Viktor Yanukovych — now living in self-imposed exile in Russia — and his Regions Party between 2007 and 2012.

US news reports surfaced this week suggesting that Mr Manafort may have received $16.7 million in secret cash payments over that period.

Ukraine's National Anti-Corruption Bureau published 22 entries on payments earmarked for the senior advisor for work conducted either on behalf of the president or his party.

The bureau's statement stressed that it could not be certain that Mr Manafort ever actually received the money. The 67-year-old firmly denies he did.

Manafort visited Ukraine several times last year

But further damage to the Trump campaign came when lawmaker Sergiy Leshchenko said that Mr Manafort also worked with the Washington lobbying group Podesta, which promoted the Regions Party and Mr Yanukovych's image in the United States.

Mr Leshchenko previously edited the Ukrainska Pravda investigative news site and later joined President Petro Poroshenko's party.

"A number of people received the money on Manafort's behalf ... There were about 10 of them," Mr Leshchenko said.

Mr Leshchenko further alleged that Mr Manafort continued to lobby for Russia's interests while working on behalf of the Opposition Bloc — a Ukrainian political group formed from the remnants of the Regions Party.

He said Mr Manafort's last contacts with the Opposition Bloc continued until 2015.

"For example, Manafort came to Ukraine several times last year. The last time this happened was in October 2015," Mr Leshchenko said.

There was no immediate response to the latest allegations from Manafort or the Trump campaign team.

AFP