Cohen's longtime business partner Evgeny Freidman pleaded guilty on Tuesday, May 22, 2018, to tax fraud in a deal that requires him to cooperate in any ongoing investigations.
But asked if he was cooperating with the authorities, Mr. Freidman would not respond.
But Cohen insisted the press was mischaracterizing their relationship, describing himself as "one of thousands of medallion owners who entrust management companies to operate" their medallions, and concluding his tweet with the hashtag #MediaWrongAgain.
Cohen is also said to have been helped by Felix Sater, a convicted ex-mobster and former business partner of Trump.
Cohen's apartment, office and hotel room were raided last month by federal investigators after getting information from special counsel Robert Mueller, who is investigating the Trump campaign's ties to Russian Federation. Last month, Federal Bureau of Investigation agents searched his home, office and hotel room.
"The government now has a strong inside witness who can assist in explaining many of Cohen's business activities and potential fraud schemes, especially when it came to valuing the medallions for loan purposes", he said.
Special Counsel Robert Mueller is conducting an extensive investigation into alleged contacts and dealings between Trump, his associates and Russian Federation, before and after the 2016 US presidential election.
The BBC reported that the Ukrainians became angered when it looked as if Cohen could not deliver on providing a substantial meeting, with negotiations apparently continuing until the day of Poroshenko's visit.
In return, Poroshenko gave Trump "a gift", the BBC reports; stifling the investigation into Manafort.
The value of a taxi medallion reached a high of $1.2 million in 2014, but their value has slumped to about $300,000 amid the rise of ride-hailing services such as Uber.
Freidman, known as New York's "Taxi King", was indicted on state charges past year by then-New York Attorney General Eric Schneiderman, who alleged Freidman and others failed to pay $5 million in MTA surcharges between 2012 and 2015. "This is a very hard day for myself and my family", Freidman said to New York Times reporter Maggie Haberman, who read the statement out loud on CNN's "Anderson Cooper 360".