Washington ? President Bush passed up a chance Wednesday to express confidence in senior aide Karl Rove in a political fight over a news leak that exposed a CIA officer’s identity. The lack of endorsement surprised some White House officials who had been told Bush would back his embattled friend.

Rove’s lawyer, Robert Luskin, later asserted that Rove had “cooperated fully” in the federal investigation, had done nothing wrong and was prepared to provide additional information to a special prosecutor if needed.

“This is a serious investigation,” Bush told reporters after a Cabinet meeting, with Rove sitting just behind him. “And it is very important for people not to prejudge the investigation based on media reports.”

Later in the day, White House spokesman Scott McClellan insisted that Rove did have Bush’s support. “As I indicated yesterday, every person who works here at the White House, including Karl Rove, has the confidence of the president,” McClellan said.

McClellan said Bush had not expressed confidence in Rove in the Cabinet session because no one had asked him that directly.

Bush said he would not discuss the matter further until a criminal investigation is finished.

Across town, a federal grand jury heard more testimony in its probe into whether anyone in the administration illegally leaked the name of CIA officer Valerie Plame in July 2003. Her husband, former ambassador Joseph Wilson, a critic of the administration’s rationale for invading Iraq, has said the leak was an attempt to discredit him.

Time magazine reporter Matthew Cooper, who wrote an article that identified Plame, appeared before the grand jury for 2 1/2 hours.

With Deputy Chief of Staff Karl Rove seen at left, President Bush speaks during a meeting in the Cabinet Room of the White House. Bush said Wednesday that he would not comment on political adviser Rove's role in leaking the identity of a CIA operative while the investigation is ongoing.

“I testified openly and honestly,” Cooper said outside the courthouse, without divulging details. “I have no idea whether a crime was committed or not. That’s something the special counsel’s going to have to determine.”

Cooper said after Wednesday’s appearance that he had no reason to believe he would be recalled to give further testimony.

Special prosecutor Patrick Fitzgerald has said that the testimony of New York Times reporter Judith Miller is also crucial to completing the investigation. Miller spent her eighth day in jail Wednesday after being held in contempt last week for refusing to cooperate.

Cooper relented only after being threatened with jail and receiving what his lawyer said were last-minute assurances from Rove that allowed him to testify about their conversation.

The dispute has taken a toll on the White House and its allies, threatening to jeopardize the president’s domestic agenda and leading to an aggressive GOP campaign to blunt Democratic calls for Rove’s firing or resignation.

With urging from the White House, Republican congressmen lined up in support of Rove and most GOP politicians outside Washington followed suit. “It’s a tempest in a teapot,” said Denzil Garrison, former state GOP leader in Oklahoma.

But some Republicans said Rove may need to go. “I think he should resign,” said Jim Holt, a Republican state senator in Arkansas who is running for lieutenant governor. “I hope Karl Rove doesn’t come gunning for me.”

Bush previously had suggested he’d fire anyone found to have been a leaker in the case.