President Bush (search) is unlikely to announce any significant changes to the nation's intelligence apparatus beyond those already made, but during Tuesday's prime-time news conference, he will try to reassure the nation about instability in Iraq.

In his third family-hour solo press briefing since he took office in the White House, the president is expected to defend his administration's response to a pre-Sept. 11, 2001, memo that warned of threats from Al Qaeda (search).

The president's speech will begin at approximately 8:30 p.m. EDT. Tune in to Fox News Channel for complete coverage.

With the administration's pre-Sept. 11 counterterrorism efforts emerging as a full-blown campaign-year issue, the president said Monday that his administration is considering making changes.

"Now may be a time to revamp and reform our intelligence services. And we look forward to hearing recommendations. We're thinking about that, ourselves and we look forward to working with the commission," Bush said Monday during a joint press conference with Egyptian President Hosni Mubarak (search) in Crawford, Texas.

Asked Tuesday to explain the revamping and reforming of the intelligence apparatus the president was considering, the White House press secretary Scott McClellan referred to big changes that have already been made, most significantly the creation of the Department of Homeland Security (search), enactment of the Patriot Act (search) and joint briefings with the directors of the CIA and FBI.

McClellan added that the president is awaiting recommendations from the Sept. 11 commission and another panel investigating pre-war intelligence on Iraq's weapons of mass destruction (search).

Reminded that the second commission won't issue a report until next January, after the election, McClellan said, "I would never rule out taking any steps sooner if they can help us better protect the American people ... The president believes there is always more that can be done."

Despite the fact that Bush has spoken positively about the work of the National Commission on Terrorist Attacks Upon the United States (search), his aides say the public hearings have been mostly a partisan exercise. They say the best work is being done behind the scenes by the staffers, and that's who they hope will guide the commission's recommendations. The commission is supposed to wrap up its investigation in July.

The president will open the news conference with a 16- to 18-minute statement on Iraq in which he is prepared to remind the country what's at stake in Iraq and repeat his commitment to transfer sovereignty to Iraqi civilians on June 30.

He will then take questions, many of which are likely to focus on a memo, entitled "Bin Laden Determined To Strike in U.S.," (search) that he received on Aug. 6, 2001, as part of the President's Daily Brief. The White House released the memo publicly after its title was revealed during the Sept. 11 commission's hearing last week with National Security Adviser Condoleezza Rice.

On Monday, Bush deflected questions about the presidential memo, and said that if the FBI had known about an imminent terrorist attack against America, the agency would have told him.

Bush will also be responding to questions about the worst few weeks of fighting since major combat operations ended in Iraq.

The president has been mostly upbeat about Iraq despite a heavy week of American casualties. U.S. troops have killed about 700 insurgents across Iraq since the beginning of the month. About 70 coalition troops — almost all Americans — have died in clashes.

"The situation in Iraq has improved in Iraq, but you're right, it was a tough week, because of — there was lawlessness and gangs that were trying to take the law in their own hands. These were people that were trying to make a statement prior to the transfer of sovereignty that they would get to decide the fate of Iraq, through violence," he said.

With the Sept. 11 commission hearings and the recent battles in Iraq being broadcast into American homes, this is a good time for Bush to defend his policies, said Stephen Hess, a political analyst at the liberal-leaning Brookings Institution (search).

"This is an administration that gets in trouble because it doesn't speak up in a timely way and defend itself," Hess said. The news conference is "really quite necessary," he said.

Karlyn Bowman, who does research on public opinion and politics at the American Enterprise Institute (search), said Bush knows there is widespread anxiety throughout the United States about the situation in Iraq.

"He has to convey being in charge and having a clear plan of what's ahead," Bowman said. "And I'm sure he will express compassion for the families" of those killed in the fighting.

"I think on 9/11, the president has to reiterate that they would have done much more if they would have had specific information," she said, adding that most Americans were not anxiously waiting to read the memo, which was declassified and released on Saturday. "I'm still not sure the public is in the mood to point the finger."

Tuesday's question-and-answer session is the 12th solo news conference Bush has held during his term in office, and the first of this year. However, he frequently holds joint press availabilities before and after meetings with his Cabinet, congressional and foreign leaders.

Still, by this point in their respective presidencies, the president's father, George H.W. Bush, had held 75 solo news conferences, Jimmy Carter had held 55, Bill Clinton had convened 40, Richard Nixon had held 25 and Ronald Reagan had conducted 22. Reagan and Nixon have held the most press conferences during prime time.

Fox News' Wendell Goler and James Rosen and The Associated Press contributed to this report.