Adding to increasing indications that war with Iraq is imminent, the White House said today that President Bush will address the nation this evening.

The president scheduled his 8 p.m. EST address a day after the United Nations was advised by Washington to withdraw its inspectors from Iraq. Reports from Baghdad indicated that the inspectors were complying with the recommendation.

In Washington, Secretary of State Colin L. Powell gave a preview of the president's address, declaring this morning that Mr. Bush ``will issue an ultimatum to Saddam Hussein.''

Mr. Powell said the ultimatum will make clear that the only way for the Baghdad regime to avoid military action against it is for ``Saddam Hussein and his immediate cohort to leave the country.''

In response to a question, the secretary said he would leave it up to the president to tell the Iraqi dictator to leave his country. And when asked whether the Iraqi leader could undertake ``any form of disarmament'' at this late hour to ``save his skin,'' Mr. Powell did not even mention disarmament in his reply.

``The time for diplomacy is past,'' Mr. Powell said. ``I can think of nothing Saddam Hussein could do diplomatically.''

At the United Nations, the United States, Britain and Spain, clearly realizing that they would not have sufficient backing, said they would not seek a Security Council vote on a resolution approving the use of force against Iraq.

The British envoy, Sir Jeremy Greenstock, said the decision now cleared the way for military action. Sir Jeremy blamed the French for the decision, saying they had made it clear they would veto any resolution.

``The co-sponsors reserve their right to take their own steps to secure the disarmament of Iraq,'' he added.

The French envoy to the United Nations, Jean-Marc de la Sabli?ere, responded by saying that there was ``a huge majority'' on the Security Council against using force in Iraq.

Word of advice to United Nations inspectors to pull out of Iraq was first disclosed by the chief nuclear weapons inspector.

Mohamed ElBaradei, head of the International Atomic Energy Agency, based in Vienna, said a similar recommendation was also given to the agency headed by Hans Blix, the United Nations Monitoring, Verification and Inspection Commission

``I immediately informed the president of the Security Council and asked for guidance,'' Dr. ElBaradei said in a report to the agency's board of governors.

``I also informed the United Nations Secretary General. I understand that the Security Council will take up the issue today. Naturally, the safety of our staff remains our primary consideration at this difficult time.''

In another sign of impending military action, the United States and Britain today urged their citizens to leave Kuwait immediately, citing the risk of chemical or biological attack.

Dr. ElBaradei, who today noted increased Iraqi cooperation in the past few weeks with the atomic energy agency, added: ``I earnestly hope - even at this late hour - that a peaceful resolution of the issue can be achieved, and that the world can be spared a war.''

Mr. Blix, however, sounded a less optimistic note today about the chances of a military conflict.

In an interview with the Swedish newspaper Aftonbladet, Mr. Blix said: ``Yes, just now it does not look like there is very much hope. But I do not have the right to give up, and neither do I want to do that. We will in any case continue and try to work until the last minute.''

At the United Nations, staff members have been preparing for a consultative session scheduled for today to discuss the latest report by Mr. Blix, chief inspector for chemical and biological weapons.

President Bush and Prime Ministers Tony Blair of Britain and Jos?e Mar?ia Aznar, following a meeting in the Azores, issued an ultimatum to the Security Council that diplomacy must end today and that war would be the inevitable next step.

Mr. Powell said that, in any event, the resolution that was not offered today ``is not a resolution we thought was necessary.''

The secretary said the United States remains committed to the United Nations, and he was sure it would survive the turmoil over how to deal with Iraq. But he added, pointedly, that he saw the indecision over what to do as ``a test that, in my judgment, the Security Council did not meet.''

United Nations officials have said the inspectors and support staff still in Iraq could be evacuated in as little as 48 hours.

Inspection teams were pulled out of Iraq in December 1998, a day before British and American warplanes began several days of air attacks after allegations that Baghdad was not cooperating with the teams.

The teams now in Iraq, which returned on Nov. 27 after a nearly four-year absence, had drawn up contingency plans to evacuate even before their redeployment.

``A lot depends on the Iraqis,'' a senior United Nations inspector told The Associated Press on condition of anonymity.

``If they let us use aircraft to get out, we could be gone in 48 hours or even less. If they won't let us fly out, we would have to drive to a border, and that could mean an eight-hour journey across hot desert. It would take longer, but we would get out.''

In Washington, the State Department ordered all government dependents and nonessential staff out of Kuwait. Britain took similar action and pared down its embassy staff and said it would close its consular and visa sections on Tuesday.

Both countries warned their citizens against travel to Kuwait, where the bulk of 300,000 troops are based, and urged nationals already there to get out while commercial flights are still running.

--http://www.nytimes.com/2003/03/17/international/17CND-NATI.html