Federal prosecutors in Manhattan are reportedly investigating President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE's personal lawyer Rudy Giuliani Rudy GiulianiThe Hill's Campaign Report: GOP set to ask SCOTUS to limit mail-in voting CIA found Putin 'probably directing' campaign against Biden: report Democrats fear Russia interference could spoil bid to retake Senate MORE's business dealings in Ukraine.

Sources familiar with the matter told The Wall Street Journal on Monday that witnesses have been questioned since at least August about Giuliani in the investigation into his work for a Ukrainian city mayor, his finances and meetings relating to the country.

ADVERTISEMENT

The investigation includes any involvement Giuliani may have had in the alleged campaign finance-related charges his business associates Lev Parnas and Igor Fruman were indicted on last week, CNN reported.

The investigation of Giuliani's bank records and business dealings in Ukraine shows the amount of attention investigators are placing on analyzing his interactions with the country, the news outlet reported.

The Journal's report expanded on reports last week that indicated federal prosecutors are examining whether the president's personal lawyer broke federal lobbying laws.

When CNN asked Giuliani if he knew of prosecutors looking into other parts of his Ukraine business dealings, he responded, "No l don't think they are but my bank records are fine."

Giuliani was named as a central figure in the whistleblower report that has now sparked an impeachment inquiry of Trump in the House.

The report detailed a call the president had with Ukrainian President Volodymyr Zelensky in which Trump asked Zelensky to look into potential 2020 opponent Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE. The whistleblower wrote about officials' concerns with Giuliani's involvement in Ukraine affairs.