NEW YORK (Reuters) - New charges are likely in a criminal campaign finance case against Lev Parnas and Igor Fruman, two associates of U.S. President Donald Trump’s personal lawyer Rudy Giuliani, a federal prosecutor said on Monday.

“We think a superseding indictment is likely,” Assistant U.S. Attorney Douglas Zolkind said at a hearing in Manhattan federal court. He did not say whether any additional defendants could expect to be charged.

Ukraine-born Parnas and Belarus-born Igor Fruman, both living in Florida, were arrested in October on charges of illegally funneling money to a pro-Trump election committee and other politicians. Both men have pleaded not guilty.

Parnas attended the hearing. Fruman did not appear, though his lawyer did.

Federal prosecutors are examining payments made to Giuliani as part of an active criminal investigation, according to a grand jury subpoena seen by Reuters. Giuliani has not been charged with a crime and has denied any wrongdoing.

He has emerged as a central figure in a fast-moving congressional impeachment inquiry into whether Trump abused his office for personal political gain by pressing Ukraine to investigate Trump’s political rival, former Vice President Joe Biden, and his son Hunter, who served as a director on the board of a Ukrainian energy company.

Parnas has said he played a role in connecting Giuliani to Ukrainian officials while Giuliani investigated the two Bidens. Current and former U.S. officials have testified that Giuliani carried out a shadow foreign policy in Ukraine.

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Trump has called the impeachment probe politically motivated and a witch hunt.

Parnas has indicated that he intends to comply with a subpoena he received from Democrats in the House of Representatives. His lawyer Joseph Bondy said at Monday’s hearing the materials requested in the subpoena include evidence in the criminal case.

Prosecutors have accused Parnas and Fruman of using a shell company to donate $325,000 to a pro-Trump election committee and of raising money for former U.S. Representative Pete Sessions of Texas as part of an effort, ultimately successful, to have the president remove Marie Yovanovitch as ambassador to Ukraine.

Prosecutors said they worked with two other men charged in the case, Andrey Kukushkin and David Correia, in a separate scheme to channel donations from a Russian businessman to U.S. politicians in order to support a proposed marijuana business.

U.S. law forbids politicians from taking foreign donations.