New York (CNN) Two men charged in a federal campaign finance case involving associates of Rudy Giuliani pleaded not guilty Thursday in Manhattan federal court.

The two defendants arraigned Thursday, David Correia and Andrey Kukushkin, are each charged with one count of conspiring to funnel foreign money into the US election system.

Two additional defendants in the case, Igor Fruman and Lev Parnas, are set to be arraigned next week. They have not yet entered a plea.

The case has received particular attention because Parnas and Fruman are linked closely to Giuliani, President Donald Trump's personal attorney, having introduced Giuliani to former and current Ukrainian officials in his effort to compile what he has claimed is damaging information on Trump's political rival, Democratic presidential candidate Joe Biden.

Giuliani himself is also a subject of the ongoing investigation by federal prosecutors, who are examining his Ukrainian business dealings, CNN has reported, and that probe includes a counterintelligence component.

Read More