A key Iraqi scientist recently told the CIA (search) that high-strength aluminum tubes bought by Baghdad weren't meant for nuclear bomb production, as President Bush suggested in his State of the Union address, two experts on Iraq's nuclear program say.

Mahdi Shukur Obeidi (search), who headed a uranium-enrichment unit vital to Iraq's pre-1991 bomb plans, "also said that since '91 they hadn't resurrected a nuclear weapon program," according to ex-Iraq inspector David Albright, an American physicist who acted as go-between for Obeidi to talk to U.S. authorities a few weeks ago.

The assertion that Baghdad had revived its nuclear project was central to the Bush administration's call for war early this year.

On March 16, three days before the U.S.-British invasion, Vice President Dick Cheney (search) said Iraq was "trying once again to produce nuclear weapons" and even that Iraq had "reconstituted nuclear weapons."

Jacques Baute (search), chief U.N. nuclear inspector for Iraq, said he also had learned, from a trusted source, of Obeidi's statements about the tubes and program status.

The Iraqi was in a position to know, Baute said. "He should have been aware if something had happened," the inspector said of claims Baghdad had revived its bomb-building.

Baute, head of the Iraq Nuclear Verification Office of the International Atomic Energy Agency (search), was interviewed at IAEA headquarters in Vienna.

Obeidi, now in Kuwait, made headlines last month when he dug up enrichment-centrifuge parts and documents he had buried in his Baghdad backyard, and gave them to the Americans. In CIA interviews, he said he hid them on orders from Iraqi leaders in 1991, during the Gulf War, for eventual use in rebuilding the bomb program, which was dismantled by U.N. inspectors after the 1991 conflict.

The White House said last month Obeidi's account was evidence of the ousted Baghdad regime's bomb ambitions. But U.S. officials did not, at the same time, report that the scientist had contradicted assertions that the program had already been revived and the tubes were part of it.

Asked Thursday in Washington about Obeidi's reported statements, a CIA spokesman declined to comment.

In his State of the Union (search) address last Jan. 28, Bush offered two pieces of purported evidence that Iraq was resuming nuclear weapons work.

The first, alleging Iraq had secretly tried to buy uranium from an African state, was later discredited when Baute's team found such claims were based on forged documents of undisclosed origin.

Bush administration officials now contend other, unspecified evidence supports that allegation, but they have not produced such evidence. Washington Democrats are demanding a major investigation of possible misuse of intelligence.

The second element in the Bush speech was the tubes.

"Our intelligence sources tell us that (President Saddam Hussein) has attempted to purchase high-strength aluminum tubes suitable for nuclear weapons production," Bush said.

Spinning cylinders made of aluminum can be used for inferior models of enrichment centrifuges, which separate out bomb uranium. But the Iraqis by 1990 had advanced to a much more productive design using carbon fiber tubes.

The Saddam government told IAEA inspectors it was buying the aluminum tubes to make small artillery rockets. The IAEA then assembled centrifuge experts to consider the question, and last March 7 IAEA chief Mohamed ElBaradei told the U.N. Security Council that documentary and other evidence strongly supported the Iraqi version. Even earlier, before Bush's speech, ElBaradei had raised serious doubts about the tubes allegation.

Albright, interviewed by telephone in Germany, said Obeidi, Iraq's top centrifuge expert, had been unequivocal in discussions with U.N. inspectors, with him and then with the CIA.

"Before the war he took the position the tubes weren't for centrifuges, and after the war" — when any fear of Saddam's dictatorial regime would have faded — "he told them the same thing," Albright said.

Baute said Iraqi centrifuge components were incompatible with such aluminum cylinders.

"They'd have to redevelop a complete research-and-development program to adapt those tubes," redesigning head caps, vacuum jackets, piping and other elements of the centrifuge assembly, said the IAEA physicist, who once helped build France's nuclear bombs.

Such enrichment programs require thousands of centrifuges in "cascade" array. Using the slower-spinning aluminum tubes would have forced the Iraqis to build many thousands more of the small, highly sophisticated machines, Albright said.

The centrifuge question had been raised legitimately, Baute said, but some U.S. officials were wrong to say the aluminum tubes could only have been destined for nuclear centrifuges.

Neither the U.S. military since March nor U.N. inspectors earlier found any signs of a revived Iraqi nuclear bomb program.

As recently as this week, the administration cited the tubes in support of its case. State Department spokesman Richard Boucher on Monday took note again of Obeidi's hidden centrifuge parts and said they should "give people pause to think that maybe that is, indeed, what these tubes were intended for."