Senior White House officials are examining aerial photographs, communications intercepts, and reports from Iraqi informants and foreign governments that purportedly show Iraqi officials intimidating Iraqi scientists and hiding weapons equipment and documents from U.N. inspectors, Bush administration officials and congressional sources said yesterday.

The intelligence includes information on what U.S. authorities say are Iraq's efforts to hide weapons and documents from U.N. inspectors, its links to al Qaeda and its purchases of equipment that could be used to manufacture banned weapons, the officials said. Secretary of State Colin L. Powell is to present the intelligence to the U.N. Security Council on Wednesday.

But the information, while constituting what officials described as a more graphic case against Iraq than presented by the administration to date, is still circumstantial, the officials said. It does not include new intelligence linking the Baghdad government to al Qaeda despite assertions by President Bush in his State of the Union address Tuesday and by British Prime Minister Tony Blair in London yesterday that the ties exist.

"There will be no single smoking gun," a senior intelligence official involved in the process said yesterday. "But it will include Iraq's concealment program of denial and deception, and what they are doing in the [chemical, nuclear and biological] weapons programs themselves."

Deputy national security adviser Stephen Hadley is leading the White House effort to sift through the intelligence with the help of the CIA, and is trying to determine what can be released without damaging the agency's ability to gather similar information, according to several intelligence officials.

"They have reached no conclusions on exactly what will be said," an intelligence official said. "But a lot more is being done this week to get a decision on what's safe to reveal." Eventually, one official said, "the president will have to make the decision."

In his speech Tuesday night, Bush announced that Powell would present new evidence to the Security Council next week to help convince skeptical council members that Iraq is in violation of U.N. resolutions and that use of force may be warranted.

"The president showed very little leg," one senior intelligence official said, "but there are those now who are wanting to push disclosure up to the thigh" when Powell appears before the Security Council.

The administration is considering declassifying more information about Iraq's purchases and attempts to buy high-strength aluminum tubing. U.S. intelligence officials believe the tubes could be used for producing weapons-grade nuclear material, but International Atomic Energy Agency analysts have determined the tubes were destined for artillery rockets.

A senior administration official said yesterday a case may be made that because the tube specifications, set by Iraq, are more precise than needed for a rocket, they could be destined for a centrifuge system associated with nuclear materials.

Almost all the new information about Iraq's alleged programs to build long-range missiles and nuclear, chemical and biological weapons will show purchases of "essentially dual-use materials," a senior intelligence official said, meaning equipment and chemicals that can be used in the manufacture of either weapons or commercial goods.

"Not all of them can have peaceful uses. Any one of them can have a safe explanation, but not all of them. Through them, we will put together a mosaic that is convincing," the official said.

To support their position that the equipment is meant for prohibited weapons programs, the United States has intelligence showing that the items were often bought covertly, using false addresses and other deceptive documentation, officials said.

Powell's presentation to the Security Council will be a multimedia event, with photos, a slide show and charts, officials said. He is expected to elaborate on Bush's statement Tuesday that "thousands of Iraqi security personnel are at work hiding documents and materials from U.N. inspectors -- sanitizing inspection sites and monitoring the inspectors themselves."

Speaking to French television yesterday, Powell said he would bring intelligence -- "some of which has not been seen before" -- that will help bolster the case made to the Security Council on Monday by Hans Blix, the head of the U.N. inspections agency, "that Saddam Hussein is trying to deny the inspectors access to weapons of mass destruction capacity within Iraq."

Powell said he also would "be presenting information and intelligence that describes some of these programs and some of these weapons."

"There's a lot of evidence," Deputy Defense Secretary Paul D. Wolfowitz told foreign journalists yesterday. Hussein has failed "to account for things we know about through a variety of sources. Some of these we probably will be able to talk about, but some of them come from people who've risked their lives to tell us."

Sen. Pat Roberts (R-Kan.), chairman of the Senate intelligence committee, said he believed the administration's new case would be compelling but circumstantial -- "the transportation of 'X,' delivered to a shed where 'Y' is thought to be happening."

"There's a strong intelligence case that Iraq has not destroyed its weapons of mass destruction and is building the capability to use them," said Rep. Jane Harman (D-Calif.), ranking member of the House intelligence committee. "There's a growing al Qaeda presence in Iraq, and I think the case can be made that there is a growing affiliation" between Baghdad and terrorist groups.

Intelligence officials yesterday outlined their concerns that publication of materials could endanger technical collection efforts or reveal human intelligence sources or defectors who want their identities kept secret. In addition, information has come from foreign intelligence agencies that do not want their roles disclosed.

"There also are future defectors or potential foreign informants who may withhold their information if they see we on occasion disclose secret data," one senior intelligence official said.

Senior members of the National Security Council have for several months debated what intelligence would be provided Blix, what would be used for an eventual public presentation and what would be preserved to help the military target weapons sites should war begin.

Illustrating the problem was the recent discovery by U.N. inspectors, based on U.S. or British information, that Iraqis may have cleaned out a site the inspectors were about to visit. Describing that incident, a senior administration official said, "The minute you reveal the information, you risk making it untrue."