WASHINGTON - Secretary of State Colin L. Powell will make a compelling case to the United Nations Security Council next week when he outlines the evidence against Iraq, but he is unlikely to produce a "smoking gun" or re-create what has come to be called an "Adlai Stevenson moment," U.S. officials say.

In choosing the forum in which Stevenson, the U.S. ambassador, confronted the Soviet Union with evidence of its deception during the Cuban Missile Crisis in 1962, the United States is playing for high stakes before a skeptical world public.

Powell will use an open meeting of Security Council foreign ministers Wednesday to display freshly declassified intelligence that officials say will show that Iraq not only possesses weapons of mass destruction but is working to conceal them.

In addition, Powell will provide evidence that the government of Iraqi leader Saddam Hussein has ties to terrorists who could use those weapons for horrific acts of mass murder, U.S. officials say.

The secretary is likely to have aerial photographs showing Iraqis moving suspicious objects out of sight of inspectors, other evidence of Iraqi attempts to smuggle illicit material, and more information than has previously been disclosed about the Iraqi regime's links to senior al-Qaida figures.

Those links are said to include the presence in Baghdad last year of al-Qaida operative Abu Musab Zarqawi, described in news reports as a specialist in chemical and biological weapons.

"I think you'll find it to be a straightforward, sober assessment - nothing theatrical - but I think we can make the case," Powell told the British television channel ITN yesterday.

"You're not going to have a big smoking gun out there," a Bush administration official said yesterday. "It's not going to be a Stevenson-type presentation."

Yet, inevitably, the Powell appearance will invite comparison with one of the most dramatic televised moments of the Cold War, when the United States, then as now, stood poised for military action and wanted to convince the world of an adversary's treachery in trying to conceal weapons of mass destruction.

Back then, the weapons in question were Soviet nuclear missiles in Cuba, 90 miles from the United States.

During an emergency meeting of the Security Council on Oct. 25, 1962, Stevenson, President John F. Kennedy's U.N. envoy, turned on his Soviet counterpart, Valerian A. Zorin, and demanded: "Do you, Ambassador Zorin, deny that the USSR has placed, and is placing, medium- and intermediate-range missiles and sites in Cuba? Yes or no? Don't wait for the translation. Yes or no?"

Zorin protested that he was "not in an American courtroom" and said Stevenson would receive an answer "in due course."

The U.S. ambassador pressed: "I'm prepared to wait for my answer until hell freezes over, if that's your decision."

Then Stevenson showed the Security Council a series of aerial reconnaissance photos of the Soviet missile sites in Cuba.

Whether or not Powell's script calls for him to confront the Iraqi envoy, Mohammed al-Douri, Bush administration officials say the evidence at Powell's disposal won't be as clear-cut as Stevenson's. Nor is Powell's case as simple to make, they say.

"People are kind of looking for a photograph or a thing that they can hold up and say, 'Aha, that proves something,'" Defense Secretary Donald H. Rumsfeld told reporters yesterday. Instead, Rumsfeld said the U.S. case rests more on a pattern of facts accumulated over time that show Hussein's ambitions to acquire weapons of mass destruction, his willingness to use them, a decade-long refusal to surrender them and aggressive assaults on neighboring countries.

The new evidence will "add to the completeness of the picture," a senior State Department official said. "We will provide additional color."

Powell, speaking Sunday to European editors, said: "Whether there will be a 'Stevenson' photo or 'Stevenson' presentation that would be as persuasive as Adlai Stevenson was in 1962, that I can't answer. ... I would love to have that kind of material to present, and we are seeing what we can do."

Powell faces a tough audience, in the Security Council chamber and around the world. Some nations on the 15-member Security Council agreed to support the U.S.-sponsored November resolution commanding Iraq to disarm in the hope that it would prevent or delay an American invasion.

Now that U.N. arms inspections are well under way, many council members want them to continue, despite all the signs described Monday by chief inspector Hans Blix that Iraqis are stonewalling inspectors and possibly hiding documents and weapons.

"We are convinced that inspections in Iraq should be continued," Russian envoy Sergei Lavrov said yesterday at the United Nations. "If countries have persuasive proof that Iraq continues its [weapons of mass destruction] program, then this proof should be presented. We would like to see undeniable proof."

Among peoples and nations overseas, "there is an overwhelming distrust of us," Sen. Joseph R. Biden Jr. of Delaware, ranking Democrat on the Senate Foreign Relations Committee, told CNN yesterday. "I have never seen us in a position where they are not only questioning our judgment, but our motives."

But Biden said the intelligence information that he's seen is persuasive. "It's the kind of evidence, if I was able to go to a jury, I'd get a conviction, I believe."

Despite threats by President Bush to go to war without Security Council approval, Powell would like to persuade a majority of the council to back a new resolution authorizing the use of force, which would signal broad international support for a U.S.-led invasion.

This would heighten pressure on Hussein to disarm - possibly preventing a war - and would provide important political cover that could enable many of America's allies in Europe and the Middle East to support the United States despite domestic opposition.

But as it works to declassify secrets and give Powell a persuasive package, the Central Intelligence Agency must be mindful that disclosure of sensitive information could expose the techniques and human sources used to obtain it.

Deputy Defense Secretary Paul D. Wolfowitz told the Council on Foreign Relations last week that the U.S. case against Iraq "comes not only from sophisticated overhead satellites and our ability to intercept communications, but from brave people who told us the truth at the risk of their lives."