Washington ? Attorney General Alberto Gonzales vowed Friday to remain on the job, digging in even as lawmakers questioned whether he could effectively run the Justice Department with no letup in the controversy over the firings of prosecutors.

Gonzales sought to explain weeks of inconsistencies about how involved he had been in decisions to dismiss the eight U.S. attorneys. He said he had been aware his staff was drawing up plans for the firings but did not recall taking part in discussions on which people would be told to go.

“I believe in truth and accountability, and every step that I’ve taken is consistent with that principle,” Gonzales said when questioned at a Boston event about preventing child sex abuse. “At the end of the day, I know what I did. And I know that the motivations for the decisions that I made were not based upon improper reasons.”

Asked why he had not resigned, as some Democrats and Republicans have demanded, he said: “I am fighting for the truth.”

Gonzales’ credibility took a fresh hit this week with the Senate testimony of his former chief of staff, Kyle Sampson, who said the attorney general was regularly briefed about plans to fire the prosecutors and was involved with discussions about “this process of asking certain U.S. attorneys to resign.”

Lawmakers impatient to hear Gonzales’ side of the story said the embattled attorney general needed to explain himself quickly – or risk more damage to his department.

“The quicker that can happen the better it will be,” said Sen. Johnny Isakson, R-Ga., adding that he would wait until hearing from Gonzales to decide whether the attorney general should resign. Gonzales is to testify April 17 on Capitol Hill, more than two weeks from now.

If lawmakers don’t fully believe Gonzales’ explanation, his ability to run the department “would be very difficult,” Isakson said.

One senior Justice aide who helped plan the firings, Michael Elston, spent Friday in a closed-door session explaining his role to House and Senate investigators.

The White House said it continued to back Gonzales “100 percent.”

President Bush “has confidence that the attorney general can overcome these challenges,” spokeswoman Dana Perino said. “And I think that you can have full confidence in somebody and believe that they still have work to do, and believe that they’re going to get that work done.”