(CNN) New flight records show that Paul Manafort traveled to Russia and Ukraine more extensively than previously known, McClatchy news reported Thursday.

President Donald Trump's former campaign manager traveled to Moscow at least 18 times prior to joining the campaign, and "was in frequent contact with Vladimir Putin's allies for nearly a decade as a consultant in Russia and Ukraine for oligarchs and pro-Kremlin parties," McClatchy reported, according to flight records the news outlet said it obtained from a government source in the Ukrainian capital, Kiev.

Manafort also took 19 trips over a 20 month-period after February 2014 while working for the pro-Russian Ukrainian Opposition Bloc party, according to the documents.

In addition to the flight records, McClatchy conducted interviews with more than a dozen individuals familiar with Manafort's activities, according to the report. CNN has not independently confirmed McClatchy's reporting.

Jason Maloni, a spokesman for Manafort, told McClatchy that Manafort "never -- ever -- worked for the Russian government."

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