(Reuters) - A grand jury has issued a subpoena related to an investigation by federal prosecutors into President Donald Trump’s lawyer Rudy Giuliani, seeking documents from former U.S. Representative Pete Sessions about his dealings with the former New York mayor and associates, the Wall Street Journal reported on Tuesday.

Citing people familiar with the matter, the Wall Street Journal reported that Giuliani is the primary focus of the subpoena, which seeks documents related to his business dealings with Ukraine and his involvement in efforts to oust the U.S. ambassador in Kiev.

Several media have reported that federal prosecutors in Manhattan are investigating Giuliani’s actions regarding Ukraine as part of a case involving two of his business associates, Lev Parnas and Igor Fruman.

The two men, who helped Giuliani investigate former Democratic Vice President Joe Biden and his businessman son Hunter, were arrested last week over what prosecutors called a scheme to illegally funnel money to a pro-Trump election committee and other political candidates.

There is no indication that Sessions, a longtime friend of Giuliani, is a target of the investigation, the Wall Street Journal reported.

Sessions spokesman Matt Mackowiak confirmed to Reuters that he was cooperating with federal prosecutors.

“Mr. Sessions is cooperating with the U.S. Attorney from the Southern District of New York and will be providing documents to their office related to this matter over the next couple of weeks as requested,” Mackowiak said.

He would not comment on the content of the subpoena.

Asked about the reports of a federal investigation, Giuliani told Reuters: “I never did any lobbying for anyone. If they want to ask me I’m happy to prove it. But they haven’t.”