WASHINGTON (CNN) -- President Bush is changing his top military and diplomatic leadership for Iraq amid speculation about his new plan for the region and pressure for change from a new Democratic Congress.
Bush said Thursday he will announce his new blueprint for the war in Iraq "sometime next week."
Adm. William Fallon, who currently oversees U.S. forces in the Pacific, has been tapped by Bush to replace Gen. John Abizaid as head of U.S. Central Command, a senior U.S. military official told CNN Friday.
Also, Lt. Gen. David Petraeus has been tapped to replace Gen. George Casey as the chief commander in Iraq, the official said.
If confirmed by the Senate, Fallon would take over Central Command which oversees U.S. forces in the Middle East, including Iraq and Afghanistan.
During his career in the Navy, Fallon commanded U.S. forces in the Atlantic and served as vice chief of naval operations, according to his biography from the U.S. Pacific Command.
Fallon is an unusual choice to head the Central Command, which has responsibility for a land-dominated region that includes the Middle East and parts of Africa.
Until now, the post has always gone to an Army or Marine general, just as the ocean-dominated Pacific Command usually goes to a Navy admiral. But because of his current service in the war Fallon does have the advantage of representing a clean slate in regard to the current Iraq policy.
In another personnel shift, Bush announced Friday that his intelligence chief, John Negroponte, is leaving his post to become deputy secretary of state -- where he's expected to handle Iraqi affairs.
Bush reached out to Negroponte about the move in an effort to increase diplomatic efforts on Iraq, an official said. (Full story)
The changes come amidst speculation about whether the president will call for additional U.S. troops to be sent to Iraq, where 3,000 Americans have already lost their lives.
The prospect of increasing troop levels has met resistance, even among some generals.
Sources with knowledge of the president's deliberations have told CNN that Bush may bolster the roughly 140,000 U.S. troops now in Iraq by an additional 20,000 to 40,000.
Democratic congressional leaders have signaled that any plan to send more U.S. troops to Iraq could receive a cool reception on Capitol Hill.
Bush talked with Iraq's prime minister, Nuri al-Maliki, about the future of the war Thursday but did not reveal any changes in U.S. strategy during their videoconference, the White House said. ()
Democrats, who assumed control of the House and Senate on Thursday, and several Republicans in Congress, have expressed skepticism about any plans to increase U.S. troop levels there.
In the November elections, "nowhere were the American people more clear about the need for a new direction than in the war in Iraq," new House Speaker Nancy Pelosi said Thursday.
"The American people rejected an open-ended obligation to a war without end."
Pelosi, a California Democrat, said the ball is in Bush's court -- and that the Iraqis must step up.
"It is the responsibility of the president to articulate a new plan for Iraq that makes it clear to the Iraqis that they must defend their own streets and their own security; a plan that promotes stability in the region and a plan that allows us to responsibly redeploy our troops," she said.
Senate Majority Leader Harry Reid, a Nevada Democrat, said any new strategy "must ensure the Iraqis take responsibility for their own future, and it must remove our troops from a dangerous civil war."
"No issue in our country is more important than finding an end to the intractable war," he said.
Bush told reporters that his nearly two-hour videoconference Thursday morning with al-Maliki convinced him that the Iraqi leader "has the will necessary to make the tough decisions."
"I will be ready to outline a strategy that will help the Iraqis achieve the objective of a country that can govern, sustain and defend itself sometime next week," Bush said. "I have still got consultations to go through."
A White House memorandum leaked in November questioned whether the Shiite Iraqi leader was capable of cracking down on sectarian violence. And al-Maliki told The Wall Street Journal last week that he never wanted his job and wished he could quit.
Bush said Thursday: "I told him, 'You show the will, we will help you.' "Levin could support 'surge'
Sen. Carl Levin, the new chairman of the Senate Armed Services Committee, said he might support a short-term increase in U.S. forces if coupled with a later reduction in American troops.
"If a temporary surge were announced as part of a reduction of forces from the current level that begins within four to six months, and there were milestones for political settlement that were not only agreed upon with the Iraqis but some of which were actually reached before the surge began, then I believe such a surge would be worthy of consideration," said Levin, a Michigan Democrat.
Levin said he and Sen. John McCain, the top Republican on the Armed Services Committee and a leading advocate of sending more troops to Iraq, have talked privately in recent days about the idea.
McCain said Thursday he's concerned Bush won't send enough troops to reinforce Iraq. He said experts he has consulted have told him as many as 35,000 additional troops should be sent.
"I need to know whether it's enough," McCain said. "I cannot support an insufficient injection of troops." ()
Meanwhile, a leading Democrat critic of the Iraq war, Pennsylvania Rep. John Murtha, told CNN an additional increase in troops "would be a phenomenal hardship on the families -- but it's not going to prove anything, because we sent another 15,000 troops into Baghdad and it's gotten worse."
For all their new power, Democrats have limited influence over a wartime commander-in-chief. One power they do have -- cutting off war funds -- is something some Democratic liberals believe should be kept on the table.
"This is the moment. We need to call our Democratic leaders to courage," said Rep. Dennis Kucinich.
Anti-war demonstrators -- some of whom disrupted a Democratic news conference Wednesday -- also say they will continue their calls to bring troops home now.Abizaid to retire
Gen. Abizaid told a Senate committee in November that troops levels "need to stay where they are." Sending 20,000 more troops to stabilize the Iraqi capital would help temporarily, but would strain an already stretched Army and Marine Corps, he said.
Abizaid has put in his retirement papers and is expected to leave his post in mid-March.
White House spokesman Tony Snow would not say whether Bush was happy with Casey's performance. "He respects what General Casey has done," said Snow.
After the November election, Bush chose Robert Gates to replace Donald Rumsfeld as defense secretary.
The U.S. ambassador to Iraq, Zalmay Khalilzad, is the leading candidate to be the next American ambassador to the United Nations, three Bush administration officials said Thursday.
CNN's Ted Barrett and Kyra Phillips contributed to this report.