US investigators secretly sought cooperation from Russian oligarchs between 2014 and 2016: report
Russian billionaire Oleg Deripaska, seen here at a June 2017 economic event in St. Petersburg, was reportedly approached by the FBI for cooperation in sensitive investigations (AFP Photo/Olga MALTSEVA)

US justice officials secretly sought cooperation from a few of Russia's richest men as they investigated Russian organized crime and possible aid from Moscow to Donald Trump's 2016 presidential campaign, The New York Times has reported.

Nearly all the half-dozen Russian oligarchs approached between 2014 and 2016 by the US Justice Department and FBI have close links to President Vladimir Putin, the newspaper said. None of them apparently cooperated.

At one point, FBI agents reportedly appeared unannounced at a home that billionaire Oleg Deripaska maintains in New York to press him on whether Paul Manafort, a onetime business partner of the Russian and briefly chairman of the Trump campaign, had served as a liaison between the campaign and the Kremlin.

A jury in Virginia last month convicted Manafort of several counts of tax and bank fraud.

Two key players in the US investigative effort, according to the Times, were Christopher Steele, the former British spy who assembled a controversial dossier on alleged links between the Trump campaign and Russia, and Justice Department official Bruce Ohr, recently the target of angry attacks from Trump.

The Steele report, which included salacious but unproven allegations about Trump -- from purported encounters with prostitutes to bribes disguised as real estate deals -- was paid for in part by supporters of Hillary Clinton, and Trump has vociferously denounced it as a "deep state" attempt to discredit him.

Robert Mueller, the special counsel investigating possible Trump campaign links to Russia, has a copy of the dossier and has reportedly interviewed Steele.

Ohr engaged with Steele repeatedly as part of the Justice Department's original investigation. Word of those contacts has fueled Republican ire and brought calls from Trump for Ohr to be stripped of his security clearance or even fired.

The Times said US officials' attempts to enlist Deripaska's help were not entirely a long shot. He had worked with the US government in an effort to rescue an FBI agent held in Iran, and he was seeking permission to travel more easily to the US.

Instead, the newspaper said, Deripaska notified the Kremlin of the American contacts.