BAGHDAD — President Bush dispatched America's top two foreign policy officials to Iraq today in separate, surprise missions calculated to demonstrate a strong show of support for the country's emerging new government.

The top American commander in Iraq expressed optimism that Iraq's selection of top government leaders marked a major step toward creating conditions that could allow a substantial number of U.S. troops to leave in the months ahead.

"I'm still on my general timeline," Army Gen. George Casey told reporters after meeting with Defense Secretary Donald H. Rumsfeld, who arrived unannounced for a daylong series of meetings with top U.S. commanders and the newly selected Iraqi leaders.

Secretary of State Condoleezza Rice flew in from Turkey a few hours later to shore up the U.S. show of support.

"We just want to make sure there are no seams between what we're doing politically and what we're doing militarily," Rice told reporters on her plane en route to Iraq. "Secretary Rumsfeld and I are going to be there together because a lot of the work that has to be done is at that juncture between political and military."

She and Rumsfeld huddled with the U.S. ambassador and other top U.S. military and civilian officials for lunch and then planned to meet jointly with the newly designated prime minister.

Rice scheduled a separate one-on-one meeting with him later.

Casey did not elaborate on his timeline for reducing U.S. forces, but he has said in the past that a "fairly substantial" reduction could be made this year if the insurgency did not grow worse and if Iraq made continued progress on the political and security training fronts.

Asked whether the breakthrough agreements last weekend to name Jawad al-Maliki as prime minister and to fill six other top government posts moves U.S. officials closer to implementing the expected troop reductions this year, Casey replied, "It certainly is a major step in the process."

He added that more needs to be accomplished on the political side, particularly in filling key government ministry jobs.

The Pentagon has not said when it expects to make decisions about further troop reductions. Casey had said late last year that he expected to submit his recommendation this spring.

"We are seeing the situation a little clearer, I'd say," as a result of the latest political progress, Casey said. "And the clearer I see it the better I can make my recommendations."