The chief United Nations weapons inspector for Iraq says Baghdad has provided new documents, which he calls a new sign of substantive Iraqi cooperation with the disarmament process. But that finding was greeted with skepticism from President Bush, just a day after the United States and Britain declared Iraq was not disarming and has already missed its final chance to do so peacefully.

Hans Blix tells reporters Iraq has provided weapons inspectors with a series of letters that could shed light on some of Baghdad's alleged chemical and biological programs. Baghdad was supposed to have destroyed its chemical and biological weapons at the end of the Gulf War 12 years ago, but after nearly three months of searching, inspectors still can not account for many banned items. Mr. Blix says the new information will help.

"There is one letter in which they tell us that they have found an R-400 bomb containing liquid in a site which is known to us in which they did dispose of biological weapons," he said. "There is another letter that tells us that they have found some hand written documents concerning the act of disposal of prohibited items in 1991."

Some of these just-received documents contain what he calls positive elements which need to be looked into further. Exactly what those elements are may be explained when weapons inspectors provide their next report to the U.N. Security Council, expected by Saturday.

It wasn't clear Tuesday whether the Bush administration had been briefed on what these new elements are. But the president told reporters he has seen nothing to indicate Iraqi leader Saddam Hussein has decided to change course.

"I suspect that he will try to fool the world one more time," he said. "After all, he's had a history of doing that for 12 years."

So far, weapons inspectors have said Iraq has generally been cooperative on process, but less so on the substantive issue of disarmament.

Iraq denies it still has any banned weapons of mass destruction. And, in an interview with the American television network CBS, Saddam Hussein also rejects a claim by weapons inspectors that Iraq's short-range al-Samoud missile is capable of flying farther than the 150-kilometer limit set by the United Nations. Hans Blix has now given Baghdad until the end of the week to begin destroying them.

But the Iraqi leader suggested to CBS he may refuse. That could end up strengthening the position of the United States and Britain at the United Nations. Both, along with Spain, say Baghdad has now missed its last chance to disarm and are calling on the Security Council to approve a new resolution that would clear the way for military action.