Washington ? Saying he wanted to be “more precise” about what he had done, Attorney General Alberto Gonzales acknowledged Monday that he had a role in approving an aide’s recommendation to dismiss several U.S. attorneys last year, but he denied that he was involved in the process of identifying which individual prosecutors should be replaced.

His remarks, in an interview with NBC News, were the first by Gonzales seeking to reconcile his public statements about his involvement in the firings with internal e-mails made public by the Justice Department on Friday.

The differences between his public words and the private e-mail traffic have added to concerns about Gonzales among members of Congress, a growing number of whom are losing confidence in his management of the Justice Department and are urging him to resign.

But the White House has said that Gonzales continues to enjoy the backing of the president. Gonzales also has said that Justice Department officials will fully cooperate with congressional investigators to show that the firings were not politically motivated, as some Democrats have alleged.

The attorney general’s efforts to clear the air were dealt a blow Monday, however, when one of his top aides, Monica Goodling, said that she would assert her Fifth Amendment right against self-incrimination rather than testify before the Senate Judiciary Committee.

Goodling, who had been the department’s liaison with the White House, had been involved in briefing Justice Department officials who earlier in March gave what some lawmakers viewed as misleading testimony about the firings. The Senate Judiciary Committee had requested that she appear voluntarily to answer questions.

John Dowd, a Washington lawyer representing Goodling, said Monday that she would not appear because the committee seemed to be prejudiced against her and the department. Dowd cited comments by several Democrats on the panel, including Sen. Charles Schumer, D-N.Y., who have characterized the earlier testimony as false and misleading.

“The hostile and questionable environment that has been created by the members of the Judiciary Committee in the present proceedings … is at best ambiguous,” Dowd said. “More accurately, the environment can be described as legally perilous for Ms. Goodling.”

Democrats questioned the decision, which some legal experts viewed as the opening of negotiations by Dowd to obtain immunity for Goodling in exchange for her testimony.

Goodling, who is still employed by the Justice Department, is on leave.

Gonzales’ former chief of staff, D. Kyle Sampson, has agreed to testify before the Judiciary Committee on Thursday. Sampson resigned March 12.