Washington ? Of all the claims U.S. intelligence made about Iraq’s arsenal in the fall and winter of 2002, it was a handful of new charges that seemed the most significant: secret purchases of uranium from Africa, biological weapons being made in mobile laboratories, and pilotless planes that could disperse anthrax or sarin gas into the air above U.S. cities.

By the time President Bush ordered U.S. troops to disarm Saddam Hussein of the deadly weapons he was allegedly trying to build, every piece of fresh evidence had been tested — and disproved — by U.N. inspectors, according to a report commissioned by the president and released Thursday.

The work of the inspectors — who had extraordinary access during their three months in Iraq between November 2002 and March 2003 — was routinely dismissed by the Bush administration and the intelligence community in the run-up to the war, according to the commission led by former Sen. Charles S. Robb, D-Va., and retired appellate court judge Laurence H. Silberman.

But the commission’s findings, including a key judgment that U.S. intelligence knows “disturbingly little” about nuclear programs in Iran and North Korea, are leading to calls for greater reliance on U.N. inspectors to test intelligence where the United States has little or no access.

“U.N. inspectors are boots on the ground,” said David Albright, a nuclear specialist who accompanied the International Atomic Energy Agency to Iraq in the mid-1990s. Albright and others think the IAEA should be given greater access in Iran, and returned to North Korea. It would be up to the agency’s board, which includes the United States, to authorize increased powers.

The Bush administration tussled with inspectors before the Iraq war and maintains a hostile relationship with the IAEA, whose director, Mohamed ElBaradei, the United States is trying to replace this year.

Months before U.S. troops attacked Iraq in March 2003, the IAEA challenged every piece of evidence the Bush administration offered to support claims of a nuclear program there, according to the commission.

In January, IAEA inspectors discovered that documents showing Iraq had tried to buy uranium from Niger were forged. But the CIA chose to stick to the claim for another six months.

Two years earlier, the IAEA disputed CIA claims that Iraq was trying to buy black-market aluminum tubes for a nuclear program. The IAEA assessment, which turned out to be accurate, was first shared with U.S. intelligence in July 2001, according to the authors of the presidential commission report.

U.S. Army task force 1-41 infantry soldiers take position at the scene of an attack against an M-1064 armored personnel carrier, burning in the background, in West Baghdad, Iraq, Friday. A report commissioned by President Bush, issued Thursday, says that all of the U.S. claims about weapons of mass destruction in Iraq had been disproved by U.N. inspectors.

Blix’s U.N. group tested evidence supplied by an Iraqi defector codenamed “Curveball,” whose tales of mobile bioweapons laboratories turned out to be fabrications, according to the report. Among Curveball’s claims was that an Iraqi facility had been redesigned, with a temporary wall, to allow mobile laboratories to slip in and out undetected.

“When United Nations Monitoring Verification and Inspection Commission (UNMOVIC) inspectors visited the site on Feb. 9, 2003, they found that the wall was a permanent structure and could find nothing to corroborate Curveball’s reporting,” the commissioners wrote.

“We offered eyes and ears,” Blix said in a telephone interview Saturday. “We knew a lot about the country, we examined places, got intelligence tips about where to go and conducted 700 inspections at 500 sites in three months.”

UNMOVIC also determined before the war that CIA claims about a fleet of pilotless Iraqi planes were incorrect. The unmanned aerial vehicles did not have the capability to deliver chemical or biological weapons.

The Bush administration has prevented the IAEA from returning to Iraq since the invasion. UNMOVIC will likely be dismantled unless the United States agrees to turn it into an international inspection force for biological weapons and missile programs.