Secretary of State Colin Powell goes before the U.N. Security Council Wednesday for a crucial briefing aimed at reinforcing the Bush administration's case that Iraq is not complying with last November's disarmament resolution, and that efforts to resolve the situation peacefully have nearly reached an end.

Mr. Powell himself said Monday he would have no "smoking gun" evidence that Iraq is hiding weapons from U.N. inspectors. But his key aides say, nonetheless, that he will build a convincing case with aerial surveillance photos and intercepted conversations among Iraqi officials that Baghdad has no intention of acceding to the international community's demand that it give up weapons of mass destruction.

The secretary spent much of Tuesday evening behind closed doors at a New York hotel preparing for the multi-media presentation, interrupting the effort only for a private meeting with Chinese Foreign Minister Tang Jiaxuan, one of 12 foreign ministers who are expected to attend the Wednesday-morning Security Council session.

Mr. Powell's address is expected to take about 90 minutes and will be followed by statements from the 14 other council member countries, and then finally a rejoinder by Iraqi U.N. ambassador Mohammed al-Douri who has been invited to take part.

U.S. officials have been secretive about the content and even the format about the secretary's presentation though they say it will include highly-classified material not previously made available U.N. inspectors or the public.

In a newspaper commentary Monday, Mr. Powell said he will offer what he termed a "straightforward, sober and compelling demonstration" that Saddam Hussein is concealing evidence of his weapons of mass destruction while preserving the weapons themselves.

On the eve of Mr. Powell's report, chief U.N. weapons inspector Hans Blix repeated his contention that Iraq's cooperation with the inspection has been adequate in terms of process but not substance.

Warning Iraq that it is "five minutes to midnight," in terms of providing full cooperation, he said Baghdad authorities should take seriously U.S. U.N. Ambassador John Negroponte's warning that the prospect of military action is looming.

"Ambassador Negroponte says that the diplomatic window is closing," said Mr. Blix. "Well, I'm listening to that and I hear others who would like to give more time, and I say that I would welcome more time, fine. But don't let's joke. We all know that the situation is very serious. I don't think a decision is final. I don't think that the end is there, that a date has been set for an armed action. I don't think so, not yet. But I think that we are moving closer and closer to it."

Mr. Blix and International Atomic Energy Agency chief Mohammed ElBaradei go to Iraq this coming weekend to appeal again for full cooperation from Iraqi authorities. The visit is to conclude just a few days before their February 14 report to the Security Council that many diplomats believe will be crucial in determining whether the council supports the use of military force.

Several members of the council including veto-wielding members China, France and Russia want inspectors to be given more time to do their jobs before any consideration of the use force. Among them is the current president of the Security Council, German Ambassador Gunter Pleuger, who told reporters Tuesday there is still time for diplomacy.

"Resolution 1441 provides a last chance to solve this problem in a peaceful way. That's what we all want," he said. "I think there is unanimity in the Council that we want to disarm Iraq, that we want to take away weapons of mass destruction and also programs to acquire or to build such weapons. And we feel that the best way of doing this is by inspections in a peaceful way."

Germany has stated its outright opposition to any military move against Iraq. Russia, meanwhile has said it is willing to "carefully examine" the new U.S. evidence but has seen no evidence this far to justify the use of force. Mr. Powell is to have a bilateral meeting with Russian Foreign Minister Igor Ivanov just before Wednesday's council meeting.