KIEV, Ukraine - A Ukrainian opposition politician who helped uncover off-the-books payments allegedly made to Donald Trump's former campaign chairman Paul Manafort says he provided the information to the FBI but never heard back from the agency.

Serhiy Leshchenko also told The Associated Press on Friday that his attempts to inform Ukrainian officials about the payments ran into roadblocks.

Manafort worked as a consultant to former Ukrainian President Viktor Yanukovych and his Party of Regions. The Russia-friendly Yanukovych was ousted in 2014 in the wake of bloody street protests and fled to Russia.

Leshchenko, a former investigative journalist, said in February he "shared some documents" with the FBI about Manafort receiving a $750,000 payment via Kyrgyzstan.

He said: "Since that moment, I have had no feedback."

In March, Leshchenko published a 2009 invoice purportedly signed by Manafort that shows a $750,000 payment for 501 computers to a company called Davis Manafort. The money came from a Belize-registered offshore company via a bank in the Central Asian state of Kyrgyzstan.

The Associated Press later obtained financial records confirming that Manafort's consulting firm had received a $750,000 payment. Manafort at the time told The AP that "any wire transactions received by my company are legitimate payments for political consulting work."

Leshchenko says letters that he sent to Ukraine's prosecutor-general about the payments were mysteriously received only months later.

He said he did not know to what extent Ukrainian authorities were investigating the payments to Manafort.

"What I know is that I sent my official letters as a member of parliament to the prosecutor-general's office and these requests were hidden. It's strange, because there were a few attempts this spring and summer to officially send documents regarding this payment," he said.

Sergei Gorbatyuk, head of the prosecutor-general's special investigations division, received the letters only at the end of the summer, Leshchenko said.

"So there were a few months of blocking this official information to him," he said in English.

News from © The Associated Press, 2017