A firm run by Donald Trump's campaign chairman directly orchestrated a covert Washington lobbying operation on behalf of Ukraine's ruling political party, attempting to sway American public opinion in favour of the country's pro-Russian government.
According to emails obtained by The Associated Press, Paul Manafort and his deputy, Rick Gates, never disclosed their work as foreign agents as required under federal law.
The lobbying included attempts to gain positive press coverage of Ukrainian officials in The New York Times, The Wall Street Journal and The Associated Press.
Another goal: undercutting American public sympathy for the imprisoned rival of Ukraine's then-president. At the time, European and American leaders were pressuring Ukraine to free her.
Gates personally directed the work of two prominent Washington lobbying firms in the matter, the emails show. He worked for Manafort's political consulting firm at the time.
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Manafort's and Gates' activities carry outsized importance, since they have steered Trump's campaign since April.
The pair also played a formative role building out Trump's campaign operation after pushing out an early rival.
Trump shook up his campaign's organisation again this week, but Manafort and Gates retain their titles and much of their influence.
The new disclosures about their work come as Trump faces criticism for his friendly overtures to Russian President Vladimir Putin.
The two men have previously said they were not doing work that required them to register as foreign agents. Neither commented when reached by the AP on Thursday.
The emails show Gates personally directed two Washington lobbying firms, Mercury LLC and the Podesta Group Inc., between 2012 and 2014 to set up meetings between a top Ukrainian official and senators and congressman on influential committees involving Ukrainian interests.
Gates noted in the emails that the official, Ukraine's foreign minister, did not want to use his own embassy in the United States to help coordinate the visits.
Gates also directed the firms to gather information in the US on a rival lobbying operation, including a review of its public lobbying disclosures, to determine who was behind that effort, the emails show.
And Gates directed efforts to undercut sympathy for Yulia Tymoshenko, an imprisoned rival of then-President Viktor Yanukovych.
The Ukrainian leader eventually fled the country in February 2014 during a popular revolt prompted in part by his government's crackdown on protesters and close ties to Russia.
Manafort did not return phone and email messages Thursday from the AP to discuss the project.
After AP reported earlier this week that Manafort helped the Ukrainian political party secretly route at least $US2.2 million ($A2.86 million) to the two Washington lobbying firms, Manafort told Yahoo News that AP's account was wrong. "I was not involved in any payment plans," Manafort said.
Gates said on Thursday he was busy with Trump campaign focus groups and promised to review AP's questions in writing, then did not respond.
Manafort also said in a statement earlier this week that he never performed work for the governments of Ukraine or Russia. Gates previously told the AP, "At no time did our firm or members provide any direct lobbying support."
Under the US Foreign Agents Registration Act, people who lobby on behalf of foreign political leaders or political parties must provide detailed reports about their actions to the Justice Department.
A violation is a felony and can result in up to five years in prison and a fine of up to $250,000.
