Casey said reductions could be coming soon, albeit slowly.

"I think as long as the Iraqi security forces continue to progress and as long as this national unity government continues to operate that way and move the country forward, I think we're going to be able to see continued gradual reductions of coalition forces over the coming months and into next year," Casey said.

Iraq's national security adviser said Sunday that he believed the number of coalition forces would drop below 100,000 by year's end. Mouwafak al-Rubaie also said the majority of coalition forces would leave before mid-2008.

Bush announced the Camp David meetings last week, as he applauded U.S. forces for conducting an airstrike that killed Abu Musab al-Zarqawi, the leader of al-Qaida in Iraq. The president has cautioned that al-Zarqawi's death will not end the war, but he says it will help.

Rep. John Murtha, D-Pa., a critic of U.S. involvement in Iraq, said Monday that now is "a perfect time" for a troop withdrawal. "People want a change in this country ... a change in direction, and I hope the president hears that and I hope the Iraqis ask us to leave," Murtha said on ABC's "Good Morning America."

"Even this attack on Zarqawi happened from the air," Murtha said. "There's no real need for us to be inside the country."

The re-evaluation of the administration's Iraq policy starts with a long day of meetings for Bush, his national security team and the military commanders. It continues with a luncheon attended by outside experts and dinner Monday night.

On Tuesday, the sessions conclude with a joint meeting via videoconference with Bush's Cabinet and top ministers in al-Maliki's new government.

Among the most immediate concerns is how to buttress security operations in and around Baghdad. Some suggest that could involve short-term troop increases.

Casey told "Fox News Sunday" that "it's not likely" that he would request more troops during the discussions, but he did not rule out bringing in more to help secure Baghdad in the future.

Casey described a "great shift" in responsibility from U.S. forces to the Iraqis over the past year. He said more Iraqis are taking the lead in the fight, although that does not mean they can operate without support such as logistics, intelligence and medical evacuations.