Washington(CNN) Federal prosecutors in Manhattan are examining Rudy Giuliani's Ukraine business dealings, including his bank records, The Wall Street Journal reported Monday, citing people familiar with the matter.

The people familiar told the paper that witnesses have been questioned by investigators since at least August about Giuliani, President Donald Trump's personal lawyer.

Part of the questioning involves any potential role Giuliani played in an alleged conspiracy involving two of his business associates, Lev Parnas and Igor Fruman, who were indicted on campaign finance-related charges last week.

CNN previously reported that Giuliani's financial dealings with Parnas and Fruman were under scrutiny by investigators, according to law enforcement officials briefed on the matter. But news of federal prosecutors examining Giuliani's bank records and business dealings in Ukraine brings into focus the level of scrutiny facing Giuliani over his involvement with Ukraine.

The Journal's report builds on reporting from The New York Times last week that Giuliani is facing an investigation by federal prosecutors into whether his involvement with Ukraine violated federal lobbying laws.

Giuliani told CNN on Monday that he was unsure if prosecutors were looking into his work with the mayor of Kharkiv, with whom he had met on a December 2017 trip as part of his international consulting business.

"It was a security report focusing on an emergency management center which was concluded in (December) or so 2017. I have no knowledge they are looking at it but let them. Maybe they should ask me instead of leaking it (if they are doing it) and I can save them unnecessary work," Giuliani said.

When asked if he was aware of prosecutors looking into any other area of his Ukraine business dealings, Giuliani told CNN, "No l don't think they are but my bank records are fine."

The former New York mayor has faced a wave of scrutiny following the release of a whistleblower complaint that alleges Trump abused his official powers "to solicit interference" from Ukraine in the 2020 election and that the White House took steps to cover it up. Trump has denied any wrongdoing.

The whistleblower complaint labels Giuliani a "central figure" in the controversy.

US officials were concerned, the whistleblower said, with Giuliani and his contacts with Ukrainian officials. The whistleblower alleges that US officials believed Giuliani was a conduit for messages between the President and officials in Kiev and that he was at the helm of a problematic "circumvention of national security decision making processes."

Giuliani has previously told CNN he has "no knowledge of any of that crap" in the complaint.