International experts are certain that Saddam Hussein has a biological weapons program but without weapons inspectors on the ground, there is no way to know whether Iraq is resuscitating nuclear or chemical capabilities.

By the time Iraq halted U.N. weapons inspections in 1998, inspectors believed the country's nuclear facilities had been destroyed and chemical materials dumped.

But that was three years ago, and even then, inspectors were convinced that Iraq — which had invaded neighboring Kuwait and fired missiles at Israel and Saudi Arabia —  was hiding the truth about its biological weapons program and its plans to build an atomic bomb.

"The biological dossier was the one that raised the largest question mark, and with every year that passes, it is all the more worrisome," said Hans Blix, director of the U.N. Monitoring, Verification and Inspection Commission for Iraq.

The Bush administration officials in recent days have accused Iraq of developing a germ warfare program.

National Security Adviser Condoleezza Rice called the Iraqi president "a threat to his own people, a threat to the region, and a threat to us because he is determined to acquire weapons of mass destruction."

Asked Monday about Iraq and potential military targets beyond the Afghanistan war, President Bush said: "If they develop weapons of mass destruction that will be used to terrorize nations, they will be held accountable."

Richard Butler, an Australian who ran the U.N. inspection program until it was forced out of Iraq in 1998, criticized the White House's stance and called for a tougher line in dealing with Iraq.

"I fail utterly to understand when the president of the United States says 'If we find they're developing weapons, we'll take action.' It's well established that they have weapons of mass destruction. The question is how much longer the U.N. Security Council will allow this to go on," Butler said.

Security Council resolutions enacted after the 1991 Persian Gulf War mandated that Iraq "unconditionally accept the destruction, removal or rendering harmless," of all chemical and biological weapons, components and manufacturing facilities, and all ballistic missiles capable of reaching beyond Iraq's borders.

The resolutions called for on-site searches of all facilities by U.N. inspectors and members of the Vienna-based International Atomic Energy Agency, which used to be run by Blix.

By the end of the Gulf War, IAEA assessments indicated Saddam was six months away from building an atomic bomb. Inspectors discovered that the oil-rich nation had imported thousands of pounds of uranium, some of which was already refined for weapons use, and had considered two types of nuclear delivery systems.

Over the next six years, inspectors took custody of the uranium, destroyed facilities and chemicals, dismantled over 40 missiles and confiscated thousands of documents and plans.

At the end of 1998, the IAEA wrote that it had "no indications to suggest Iraq was successful in its attempt to produce nuclear weapons," or that there remains "any physical capability for the production of amounts of weapons-usable nuclear material of any practical significance."

Butler's findings, which centered on the biological, chemical and missile capabilities, were not as definitive. Iraq had used chemical weapons twice in the 1980s against its Kurdish population and during the Iran-Iraq war.

"I entered a final report showing that not all their weapons of mass destruction had been accounted for," Butler said.

It was Iraq's refusal to cooperate with Butler's team that prompted punishing U.S. and British airstrikes in December 1998. As a result, Iraq would not let weapons inspectors back in to the country and has argued that it has fulfilled its U.N. obligations.

In an Oct. 5 report to the Security Council, IAEA chief Mohamed ElBaradei wrote that "for nearly three years, the agency has not been in a position to implement its mandate in Iraq. As a consequence, it is not able at present to provide any assurances that Iraq is in compliance with its obligations."