WASHINGTON - The Bush administration is initiating a series of diplomatic and military steps that must be completed before the United States could go to war in Iraq, American and allied officials say.

The tasks, some of which could take weeks or even months, include formalizing allies' roles in any offensive, discouraging neighboring countries from launching their own strikes against Iraq and deciding whether to seek United Nations support for an attack. Failure to accomplish many of these objectives could delay or complicate the onset of war.

The administration is moving urgently to accomplish its objectives, even before the start of U.N. weapons inspections. One goal is to create a credible threat of force, which might pressure President Saddam Hussein of Iraq to comply with the new resolution of the U.N. Security Council. The other main reason for acting speedily is to be ready for combat in Iraq before hot weather sets in there next year.

There has been some progress, officials said.

U.S. officials have privately secured informal permission for basing and overflight rights from several Central Asian and Persian Gulf nations, including Kuwait and Qatar, but those commitments need to be formalized. Defense Secretary Donald H. Rumsfeld is expected to consult with allies this week at the NATO meeting in Prague, Czech Republic, on how they might fill in for U.S. forces now in Europe that would be moved to the gulf region.

The United States has stockpiled tanks and heavy equipment for more than 30,000 troops in several gulf nations and on ships nearby.

U.S. diplomats have intensified talks with two important allies, Turkey and Israel, to persuade them to remain on the sidelines during an invasion. Quietly, often through informal channels, Washington has also broached discussions with Iran about preventing Iraq's Shia majority from trying to seize control of Baghdad or form a separate state if Hussein falls.

If Hussein defies or obstructs weapons inspectors, the Bush administration will have to decide whether to seek approval from the Security Council for a military strike. Administration officials said President Bush would like council support, provided it can be obtained quickly.

Finally, any military campaign against Iraq would begin with a psychological campaign intended to turn Hussein's forces against him. Rumsfeld has approved the outlines of an ambitious plan that goes beyond traditional leaflet drops and broadcasts, a senior Defense Department official said.