Jury selection began Tuesday in the case against I. Lewis (Scooter) Libbey, a former Bush adviser and chief of staff to Vice-President Dick Cheney.

Libby is accused of lying to investigators about his conversations with reporters about CIA officer Valerie Plame.

Plame's name and job were leaked to the press after her husband publicly criticized the Bush administration's pre-Iraq war intelligence.

Dozens of potential jurors were asked their opinions of the Bush administration and Cheney, but not about their views on the Iraq war or whether they had family or friends who served in the military — questions Libby's lawyers had hoped would be asked.

"Do any of you have feelings or opinions about the Bush administration or any of its policies or actions, whether positive or negative, that might affect your ability to give a former member of the Bush administration a fair trial?" U.S. District Judge Reggie Walton asked about 60 potential jurors.

Cheney to testify

The vice-president is expected to be a key defence witness. Presidential historians believe it would be the first time a sitting vice-president testified in a criminal case.

White House press secretary Tony Snow declined to discuss the case Tuesday. Asked about the possibility of a presidential pardon for Libby, he replied: "I'm not aware of any discussions about a pardon."

The leak of Plame's identity touched off a political scandal and an FBI investigation that Libby is accused of obstructing. Lawyers for both sides want to know how closely potential jurors have been following the case.

Walton prohibited jurors from reading newspapers, watching TV news or listening to the radio. He said court officials would screen newspapers and provide jurors with edited copies to read.

After the group was asked 38 questions, each juror was scheduled to take the stand for followup questions from defence lawyers, prosecutors and the judge.

Opening arguments are scheduled to begin on Monday. The trial is expected to last four to six weeks.

With files from the Associated Press