(CNN) A grand jury has subpoenaed former Republican Rep. Pete Sessions on matters connected to President Donald Trump's personal attorney Rudy Giuliani, two Giuliani associates' dealings with Ukraine and efforts to remove the US ambassador to Ukraine, sources familiar with the matter told CNN.
Sessions' subpoena suggests that investigators are looking to gather information on his interactions with Giuliani, as well as with associates Lev Parnas and Igor Fruman -- who were indicted for allegedly funneling foreign money into US elections -- as the investigation into their Ukraine dealings charges forward.
CNN has reported that prosecutors allege Parnas and Fruman asked Sessions to help get the US ambassador to Ukraine fired at the same time that they were committing to raise tens of thousands of dollars for Sessions' reelection campaign. Parnas made their request to the congressman in part at the behest of one or more Ukraine government officials, the indictment states.
The subpoena to Sessions came in the last few days after the indictment against Parnas and Fruman was made public, according to the source and another source familiar with the matter.
The second source refused to rule out that Sessions himself is not a target of the grand jury investigation, saying instead that the investigation has "not reached definitive conclusions."
The Wall Street Journal first reported that Sessions had been subpoenaed.
Sessions "is cooperating with the US 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," spokesman Matt Mackowiak said.
Mackowiak declined to specifically comment on reports that Sessions had received a grand jury subpoena for documents related to Giuliani's Ukraine dealings and his communications with Giuliani, Parnas and Fruman.
A spokeswoman for the Manhattan US attorney's office declined to comment on the subpoena.
Giuliani said Saturday that he's not aware he's under investigation for his involvement in the unraveling Ukraine scandal.
His financial dealings with Parnas and Fruman, though, are under scrutiny by investigators overseeing the case, law enforcement officials briefed on the matters previously told CNN. Trump also pressed Ukrainian President Volodymyr Zelensky in a July 25 call to work with Giuliani to investigate former Vice President Joe Biden and his son, Hunter, despite there being no evidence of wrongdoing by either Biden.