WASHINGTON -- The White House acknowledged Monday that senior aides to President Barack Obama knew a month ago that the Internal Revenue Service had targeted conservative groups, expanding on previous administration statements about who in the White House knew about the inquiry and when they knew about it.

Until now, the White House had said that only White House Counsel Kathryn Ruemmler had been told of the investigation of the IRS, and that her office had been informed the week of April 22. Monday, the White House said the counsel’s office had been alerted to the IRS inquiry earlier, and that more senior advisers in the West Wing were told, including Chief of Staff Denis McDonough and other aides the administration refused to name.

While the story evolved, the White House insisted anew that no one in the White House knew of the practice of targeting conservative groups until the inquiry was almost done, and that no one told the president even about the inspector general’s investigation until it was reported publicly by the IRS itself.

“It is entirely appropriate that the president not be notified of something of an ongoing . . . audit of the IRS activity,” White House Press Secretary Jay Carney said. “The suggestion of alerting him is that then he would do something. And if he were to do something, imagine what that story would look like. . . . It is absolutely a cardinal rule, as we see it, that we do not intervene in ongoing investigations.”

Obama has been under intense scrutiny for his administration’s handling of the IRS controversy. Some lawmakers have faulted the administration for not acting fast enough, while others have grown suspicious of his aides’ repeated comments that they did not know about the allegations beforehand. Monday’s about-face is likely to set off a new firestorm.

“I think there’s going to be a gradual disclosing of various parts of this issue,” said Sen. Orrin Hatch of Utah, the top Republican on the Senate Finance Committee.

“The inspector general’s audit – initiated at the request of members of Congress – was a good start, but it’s clear there’s much more that must be explored, including how this targeting was able to continue for so long without the administration acting to stop it,” said Brendan Buck, a spokesman for House Speaker John Boehner, R-Ohio. “As the bipartisan investigation unfolds, it would be wise for the administration to offer less arrogance and more honesty.”

Carney said Monday that White House officials were told last month that groups that used “tea party,” “patriot” or similar words associated with the conservative tea party movement were selected, but they did not see a draft of the pending special inspector general’s report until it was made public.

“We knew the subject of the investigation, and we knew the nature of some of the potential findings, but we did not have a copy of the draft report, we did not know the details, the scope or the motivation surrounding the misconduct, and we did not know who was responsible,” Carney said. “Most importantly, the report was not final and still very much subject to change.”

Last week, Carney said the White House counsel’s office had been notified the week of April 22 of a coming inspector general report on the IRS. He denied that anyone knew of the IRS practices before that.