A man accused of jumping a fence at the White House pleaded not guilty Wednesday to charges that he ran into the presidential mansion while carrying a knife.

A lawyer for defendant Omar J. Gonzalez, David Bos, entered the plea on his client's behalf in a 20-minute proceeding that grew contentious because of a disagreement between Bos and U.S. Magistrate Judge Deborah Robinson.

Wearing a standard prison-issue orange jump suit, Gonzalez sat attentively at the defense table but did not address the court.

Robinson wants Gonzalez to undergo a forensic screening to determine whether he is competent to stand trial. Bos opposed that, telling reporters he does not want to provide the government with an extensive amount of information about his client that would be revealed by a forensic screening.

Bos said Gonzalez is competent to stand trial, an assertion that marked the start of a dispute over whether Gonzalez will have to undergo the screening.

A three-count federal grand jury indictment issued Tuesday accuses Gonzalez of unlawfully entering a restricted building while carrying a deadly weapon, a federal charge. He also was indicted in the Sept. 19 incident on two violations of District of Columbia law -- carrying a dangerous weapon outside a home or business and unlawful possession of ammunition.

Following Gonzalez's arrest, investigators recovered more than 800 rounds of ammunition, a machete and two hatchets in his car. The indictment said the ammunition consisted of eight types, including 12 gauge shotgun shells and .45 caliber rounds.

The judge handling the case will be U.S. District Judge Rosemary Collyer, who was nominated for the post in the first term of President George W. Bush. She had been general counsel of the National Labor Relations Board from 1984-1989 and chairman of the Federal Mine Safety and Health Review Commission from 1981 to 1984.