WASHINGTON — Testimony at the trial of I. Lewis Libby Jr., who served as Vice President Cheney’s chief of staff, is laying bare how the White House scrambled to contain the damage after the credibility of a claim that President Bush made about Iraq’s nuclear program came under public attack in July 2003.

The rare window into the inner workings of the administration indicated that Mr. Cheney and his staff acted aggressively and sometimes unilaterally to deflect an intensifying maelstrom of press accounts disputing the contention in Mr. Bush’s State of the Union address that Iraq had recently sought uranium in Africa. Some efforts by Mr. Libby in particular prompted suspicion and a rebuke from Mr. Bush’s deputy national security adviser at the time, Stephen Hadley, according to a former head of Mr. Cheney’s public affairs staff, Catherine Martin.

Under questioning by prosecutors, Ms. Martin testified that at a morning meeting of senior staff, Mr. Hadley expressed irritation at an NBC news report that the White House was faulting the CIA for mishandling the president’s speech and the so-called 16 words about uranium in Africa.

“Hadley raised the evening news report by Andrea Mitchell and said there had been suggestions that the White House was pushing blame towards the CIA,” Ms. Martin said. She recalled Mr. Hadley saying, “That was not what we should be doing, and that was not helpful,” and adding that the director of central intelligence, George Tenet, was upset about the report.

Ms. Martin said it seemed Mr. Hadley, who has since become the president’s principal national security adviser, was blaming her. “He turned and looked at me,” she said. “I felt like he was suggesting I’d been involved in talking to the reporters.”

Ms. Martin said the official in the vice president’s office who talked with Ms. Mitchell prior to her report was Mr. Libby, who was sitting right in front of Ms. Martin at the meeting. Asked what Mr. Libby did when Mr. Hadley spoke, Ms. Martin said Mr. Libby “looked down.”

Mr. Hadley was so exercised about the news report that he held another session with just the public affairs staff. “He told us again we should not be pointing fingers. …This was not helpful to the president,” she recalled.

Ms. Martin said she immediately sought out Messrs. Cheney and Libby and told them that she thought she was being accused of helping to circulate the criticism of the CIA. The only response that she described was that soon thereafter she and other communications staffers were told they were being frozen out of all discussions about the so-called 16 words.

Prosecutors elicited that story and entered into evidence a series of “talking points” memos prepared by Messrs. Cheney, Libby, and others, in an apparent effort to show how focused top officials were on responding to a one-two punch delivered by a former ambassador, Joseph Wilson IV, on July 6, 2003. On that Sunday, Mr. Wilson published an op-ed piece in the New York Times and appeared on NBC’s “Meet the Press” to describe a trip that he took to Africa on behalf of the CIA to investigate claims that Iraq sought uranium in Niger. Mr. Wilson said his inquiry had ruled out that possibility, and therefore, Mr. Bush should not have touted it in his speech. The former ambassador also made some assertions that turned out to be misleading or false, including claims that his Africa trip was taken at the behest of Mr. Cheney and that the vice president must have known of the findings.

The glimpses of the behind-thescenes maneuvering overshadowed the more basic contribution that Ms. Martin made to the prosecution case yesterday by confirming that she told Mr. Libby, before it was publicly reported, that Mr. Wilson’s wife, Valerie Plame, worked at the CIA. It is the disclosure of Ms. Plame’s identity that led to the criminal investigation.

“I remember saying, ‘Apparently his name is Joe Wilson, he was a chargé in Baghdad, and his wife works over there,'” at the CIA, Ms. Martin said. She could not pinpoint precisely when the conversation took place, but she said it was no later than July 6 and probably happened on or about June 11.

Mr. Libby is charged not with leaking Ms. Plame’s identity but with lying to the FBI and a grand jury about how he learned about Mr. Wilson’s wife and about related discussions he had with reporters.

Ms. Martin’s testimony could undermine Mr. Libby’s claim that he once thought he learned about Ms. Plame from an NBC News journalist, Timothy Russert. However, her testimony about another conversation key to the case was more ambiguous.

Prosecutors contend that when Mr. Libby spoke by phone to a Time magazine reporter, Matthew Cooper, on July 12, 2003, the vice presidential aide contributed evidence of Ms. Plame’s CIA affiliation by saying, in response to a question, that he had heard that fact. Mr. Libby concedes some such discussion, but he contends that he said he’d heard about Ms. Plame from reporters and couldn’t vouch for the accuracy of the talk.

Ms. Martin said she heard a portion of Mr. Libby’s end of that conversation but that she does not recall any mention of Mr. Wilson’s wife or what other reporters were saying.

Ms. Martin, who is the first current White House staffer to take the stand, left the vice president’s office in early 2004 and now works on communications for the president’s economic advisers.

The next witness expected is a former White House press secretary, Ari Fleischer. It was disclosed earlier this week that Mr. Fleischer was granted immunity after refusing to cooperate with the special prosecutor on the case, Patrick Fitzgerald.

“Frankly, I didn’t want to give him immunity because I didn’t know what we were getting,” Mr. Fitzgerald said in court yesterday. “I was buying a pig in a poke.”

The comments came as the prosecutor argued with defense attorneys about whether questioning Mr. Fleischer could include showing the jury news accounts that said people who discussed Ms. Plame with the press might end up serving lengthy prison terms.

Mr. Fitzgerald said he suspected Mr. Fleischer leaked information about Ms. Plame but couldn’t get to the bottom of it. “We understood he’d given it out to someone, but we didn’t know which reporters,” the prosecutor said. “I had a sense he knew something important.”

Mr. Fitzgerald said Mr. Fleischer’s lawyers, from Williams & Connolly, declined to provide details without the immunity, which was granted after the former press secretary took the Fifth Amendment in front of the grand jury.

An attorney for Mr. Libby, Theodore Wells Jr., earlier identified an NBC News reporter, David Gregory, as one recipient of Mr. Fleischer’s information about Ms. Plame.

Meanwhile, Mr. Fitzgerald expressed doubts yesterday that defense attorneys will go through with their stated intention to put Mr. Libby on the stand. One of Mr. Libby’s key defenses is that he might have innocently forgotten some conversations, but Judge Reggie Walton said he will bar the memory defense from closing arguments if the defendant elects not to testify.