The government's most definitive account of Iraq's arms programs, to be released today, will show that Saddam Hussein posed a diminishing threat at the time the United States invaded and did not possess, or have concrete plans to develop, nuclear, chemical or biological weapons, U.S. officials said yesterday.

The officials said that the 1,000-page report by Charles A. Duelfer, the chief U.S. weapons inspector in Iraq, concluded that Hussein had the desire but not the means to produce unconventional weapons that could threaten his neighbors or the West. President Bush has continued to assert in his campaign stump speech that Iraq had posed "a gathering threat."

The officials said Duelfer, an experienced former United Nations weapons inspector, found that the state of Hussein's weapons-development programs and knowledge base was less advanced in 2003, when the war began, than it was in 1998, when international inspectors left Iraq.

"They have not found anything yet," said one U.S. official who had been briefed on the report.

A senior U.S. government official said that the report includes comments Hussein made to debriefers after his capture that bolster administration assertions, including his statement that his past possession of weapons of mass destruction "was one of the reasons he had survived so long." He also maintained such weapons saved his government by halting Iranian ground offensives during the Iran-Iraq war and deterred coalition forces from pressing on to Baghdad during the 1991 Persian Gulf War, the official said.

The official also said that Duelfer's Iraq Survey Group had uncovered Iraqi plans for ballistic missiles with ranges from 400 to 1,000 kilometers and for a 1,000-kilometer-range cruise missile, farther than the 150-kilometer range permitted by the United Nations, the senior official said.

The official said Duelfer will tell Congress in the report and in testimony today that Hussein intended to reconstitute weapons of mass destruction programs if he were freed of the U.N. sanctions that prevented him from getting needed materials.

Duelfer's report said Hussein was pursuing an aggressive effort to subvert the international sanctions through illegal financing and procurement efforts, officials said. The official said the report states that Hussein had the intent to resume full-scale weapons of mass destruction efforts after the sanctions were eliminated, and details Hussein's efforts to hinder international inspectors and preserve his weapons of mass destruction capabilities.

Rep. Jane Harman (D-Calif.), vice chairman of the House intelligence committee, said she had not read Duelfer's report but has been told that it thoroughly undercuts the administration's assertions that Iraq posed a serious threat.

"Intentions do not constitute a growing danger," Harman said. "It's hardly mushroom clouds, hardly stockpiles," she added, a reference to administration rhetoric used in the run-up to the war.

The report's release comes at a point in the presidential campaign when Democratic candidate John F. Kerry is aggressively challenging the Bush administration about its prewar justifications for invading Iraq, which centered largely on the contention that Hussein possessed weapons of mass destruction. People familiar with the report said it is being released today because Duelfer was ready and his schedule permitted him to testify to Congress.

Yesterday, administration officials discussed some of the report's findings publicly, arguing that it showed Hussein was a long-term threat even though no weapons of mass destruction were found.

White House press secretary Scott McClellan called Hussein's effort to evade the U.N. sanctions "very revealing." "We all thought that we would find stockpiles, and that was not the case," McClellan said.

"The fact that he had the intent and capability, and that he was trying to undermine the sanctions that were in place is very disturbing. And I think the report will continue to show that he was a gathering threat that needed to be taken seriously, that it was a matter of time before he was going to begin pursuing those weapons of mass destruction."

The report includes page after page of names of individuals and companies -- many from China, Russia and France -- that had traded illegally with Iraq, the senior government official said. The State Department began briefing the named governments on the report yesterday, the official said.

Duelfer's findings follow reports by the Senate intelligence committee and his predecessor, David A. Kay, that criticized the prewar assessment that Iraq had chemical and biological weapons. But Bush has pointed to the Duelfer report as the last word on the state of Iraq's weapons programs. Asked in June if he thought such weapons had existed in Iraq, Bush said he would "wait until Charlie gets back with the final report."

Another government official who was briefed on the report said that many U.S. officials had thought Hussein would "get down to business" in developing weapons when the U.N. inspectors left. "There's no evidence of that," the official said.

The official said that Iraq's nuclear-related activity in particular had been dormant for years before the invasion. "They probably didn't have a program for some period of time, well before we went in there," he said.

The Bush administration has held out the possibility that illicit weapons and their components were secreted by Hussein across the border into Syria. This may still be true, but Duelfer's team did not find any proof to support this notion, the official said. "They have no evidence of this," the official said. "It's an unresolved issue." Syria denies it aided the hiding of illicit materials.

Duelfer replaced Kay in January as the chief U.S. weapons hunter after the U.S.-led invasion of Iraq. In title, he was the CIA's special adviser for strategy regarding Iraq's weapons of mass destruction. As head of the Iraq Survey Group, he worked independent of the CIA and his report was not vetted or changed by the agency, said one U.S. government official familiar with Duelfer's work.

The president met with Duelfer at the White House on Feb. 6. Bush said during a prime-time news conference in April that during Duelfer's return to Iraq, he had been "amazed at how deceptive the Iraqis had been" toward U.N. inspectors, as well as "deceptive in hiding things."

The report also includes an investigation of a broad range of subjects that are either loosely or not at all connected to weapons of mass destruction, a foreign intelligence official said. These include Iraq's conventional weapons programs, evidence of corruption and abuse in the U.N.-monitored oil-for-food program, and dual-use equipment -- which could be used for either peaceful or military programs -- that U.N. inspectors may not have been aware of.

Staff writer Dafna Linzer contributed to this report.

Charles A. Duelfer wrote that Iraq did not have the means to produce unconventional weapons.