Former New York State Assembly Speaker Sheldon Silver pleaded not guilty to an extortion and fraud indictment during a brief appearance on Tuesday in federal court in Manhattan.

Silver's lawyers said they were moving immediately to dismiss the case based on news conferences and speeches by U.S. Attorney Preet Bharara, which they said improperly prejudiced both the grand jury that indicted Silver and any future trial jury.

"These were situations where the U.S. attorney excoriated the defendant and basically deprived him of his presumption of innocence and extolled his guilt," said defense lawyer Steve Molo.

Silver, 71, whose January arrest on charges that he used his seat of power to get $4 million in kickbacks led to his resignation as speaker, was released pending trial by U.S. District Judge Valerie Caproni.

In a corruption case that has shaken Albany, prosecutors allege that Silver profited from two different schemes. He is accused of giving state funds to a doctor's mesothelioma research in return for patient referrals to a law firm that paid him, and referring real estate developers with state business to another law firm that paid him.

Bharara contends Silver "amassed a tremendous fortune" by exploiting his office for personal gain. In court Tuesday, a prosecutor from Bharara's office called Molo's allegation "baseless."

After his arrest on a criminal complaint, Silver -- who had held the speakership for more than 20 years -- was replaced by Bronx Assemb. Carl Heastie. Silver, a Democrat, continues to represent his Lower East Side district.

Although he has said all along that he believes he will be vindicated at trial, Silver had not formally entered a plea until Tuesday. He is charged with wire fraud, mail fraud and extortion.