Washington ? By any normal gauge, the war with Iraq is over. Saddam Hussein’s government is gone, all key cities are seized, major combat is winding down and two aircraft carriers are going home.

Yet major questions remain, including the whereabouts of Saddam and any weapons of mass destruction and whether Iraqis can govern themselves after a quarter-century of one-man rule.

The role of the United Nations or individual nations in Iraq’s future also is up in the air. The United States has invited its coalition partners to talks on rebuilding Iraq — but not countries that objected to the war such as Germany, France and Russia.

Some of these loose ends could take months or even years to tie up, analysts suggest.

But for now, nobody is disputing the immediacy or decisiveness of the allied military successes.

Saddam’s “regime is in disarray and no longer in control of Iraq,” said Brig. Gen. Vincent Brooks at Central Command headquarters in Qatar. Maj. Gen. Stanley McChrystal said Monday at the Pentagon, “I would anticipate that the major combat operations are over.”

Administration officials basked in the details:

l There have been relatively few allied casualties: As of Monday, 121 American and 31 British service members had died. Four American troops remained missing. Eight U.S. prisoners of war were rescued.

l All oil fields in Iraq were under coalition control. On Sunday, Kuwaiti firefighters extinguished the last oil well fire in southern Iraq. One was still burning in the north.

l While looting continues and there are humanitarian concerns, including shortages of food, water and hospital beds, there was no mass exodus of Iraqi refugees.

With the U.S.-British military victory sealed, the world’s attention was shifting rapidly to the reconstruction of Iraq.

Iraqi men take a break in front of a U.S. Marine armored vehicle in central Tikrit, Iraq. Marines on Monday overran loyalists staging a last stand at Saddam Hussein's hometown of Tikrit, ending the major combat phase of the Iraq war.

“Among all the unanswered questions, the most complex and most relevant is how the Iraq people will help themselves establish some foundation for democracy,” said Phil Anderson of the Center for Strategic and International Studies.

Iraqis have lived under Saddam’s rule for 24 years and have little experience in self-government. Already, tensions have flared between Iraqi nationals and expatriates who are beginning to return. The makeup of the interim Iraqi government envisioned by the administration is undecided. The country includes three distinct ethnic groups who mistrust one another.

“Our concern is that Iraq would disintegrate and fall into sectarian strife and civil war,” Mohammed Al Sabah, Kuwait’s foreign minister, said Monday as he dashed from a meeting with Vice President Dick Cheney to one with Secretary of State Colin Powell.

“So far, thank God, things have been holding up,” he added.

Ethnic tensions in Iraq were accentuated by Saddam “as a way to divide and rule,” said Jon Alterman, a Middle East expert and former secretary of state for Near Eastern affairs. This could make it even harder to form a stable, eventually democratic, government, he suggested.

Still, Iraq’s vast oil reserves — the world’s second largest after Saudi Arabia — will help any new Iraqi government solidify its power, Alterman said. “Iraq’s new government will get the money from that oil. That makes it potentially strong.”

As to Saddam’s fate, many U.S. officials and military analysts believe he probably died in last week’s bombing that targeted him and his sons. If alive, U.S. military officials say, Saddam is not exercising any military control.

U.S. Marines on Monday seized Saddam’s hometown of Tikrit, his final stronghold, while Washington turned up the heat on Syria, warning it not to shelter fleeing Iraqi officials or to advance a mass-destruction weapons program.

While some U.S. forces were leaving — including those assigned to the carriers USS Kitty Hawk and the USS Constellation — other ground troops were just arriving, reflecting the end of the air war and the new focus on reconstruction and security.

“For the last several weeks, we’ve had to worry about Iraqis killing American forces. Now we have to start worrying about Iraqis killing Iraqis,” said veteran diplomat James F. Dobbins, who was Bush’s special envoy for Afghanistan. “It now falls to the United States to reimpose order.”