Igor Fruman arrives at federal court for an arraignment hearing on October 23, 2019 in New York City.

Two associates of President Donald Trump's personal lawyer Rudy Giuliani pleaded not guilty Wednesday in federal court in Manhattan to criminal charges related to an allegedly illegal donation to a Trump-linked PAC and other actions.

The two men, Lev Parnas and Igor Fruman, have been working with Giuliani in his effort to uncover damaging information about former Vice President Joe Biden in Ukraine.

That effort and Trump's pressuring of Ukraine to investigate Biden is at the center of an ongoing impeachment inquiry into Trump.

During Wednesday's arraignment, a lawyer for Parnas raised concerns with Judge Paul Oetken that there is a chance that federal authorities involved in the case could have seized documents or communications that might be protected by Trump's executive privilege.

The lawyer, Edward McMahon, said that possiblity exists because of the fact that Parnas worked with Giuliani, and because Trump also has had interactions with Giuliani.

Parnas and Fruman are accused of making a $325,000 illegal straw donation to a Trump political action committee, and making another $15,000 in illegal donations to another committee.

The men are accused of hiding the fact that the money came from a foreign national. Foreigners are barred from contributing to campaigns for federal office.

During the same month they donated the money to the Trump PAC, Parnas posted photos on Facebook of himself and Fruman with Trump, as well as with Donald Trump Jr., the president's eldest son.

The charges against the two men, who were arrested Oct. 9 at Dulles International Airport in northern Virginia as they were about to board a flight to Vienna with one-way tickets, include conspiracy, making false statements to the Federal Election Commission and falsification of records.

An indictment accuses them of a scheme to help former Ukraine Chief Prosecutor Yuriy Lutsenko and a person who is described as having "Russian roots" gain access to U.S. politicians and government officials through campaign contributions to advance business and personal financial interests.

Fruman and Parnas' co-defendants, David Correia and Andrey Kukushkin, were arraigned last week and pleaded not guilty to a single conspiracy count.

Parnas, who is a native of Ukraine, was freed on $1 million bond secured by $200,000 cash. Fruman, who was born in Belarus, is free on the same amount of bond, secured by $100,000 cash and a Florda condominium valued at $900,000.

Both men must stay in their Florida homes and be monitored by a GPS device as a condition of their bonds.

At the arraignment McMahon, Parnas's lawyer said the case involved "a lot of information" that is covered by "attorney-client" privilege "and perhaps executive privilege information."

Executive privilege refers to a president's right to keep information related to executive branch actions confidential.

"We have Mr. Giuliani working for the president of the United States," said McMahon. "These are issues we need to be sensitive to."