United Nations Security Council members have called on the Bush Administration to allow UN weapons inspectors to return to Iraq to certify whether Baghdad possessed biological and chemical weapons before the war.

But their plea was shrugged off by President George Bush, who vowed to "reveal the truth" about Saddam Hussein's weapons of mass destruction.

The call for a resumption of UN inspections, which was endorsed on Thursday by an overwhelming majority of council members, including Britain, America's closest military ally, came as the Bush Administration faces charges by members of Congress and some intelligence analysts that it may have exaggerated the threat posed by Iraq to justify the invasion.

It also reflected a growing consensus in the 15-nation council that the UN Monitoring, Verification and Inspection Commission (UNMOVIC) should test US and British claims that Iraq continued to develop chemical, biological and nuclear weapons.

"The disarmament of Iraq must be verified and confirmed by UNMOVIC and the International Atomic Energy Agency on the ground and in conjunction with the coalition," France's UN ambassador, Jean-Marc de la Sabliere, told the Security Council.

In his farewell appearance before the Security Council, the chief UN weapons inspector, Hans Blix, said Iraq's failure to account for its alleged biological, chemical or nuclear weapons did not mean that it possessed them - or posed an imminent threat.

"There remain long lists of items unaccounted for, but it is not justified to jump to the conclusion that something exists just because it is unaccounted for," he said.

Dr Blix, who retires at the end of the month, said he could not verify claims by Mr Bush and other senior US officials that two trucks discovered in Iraq were mobile biological weapons production plants.

But Iraq had apparently violated its obligation to declare their existence to UN inspectors. "We will make absolutely no assessment without having seen them."

The US ambassador to the UN, John Negroponte, said the Iraq Survey Group, established by the Pentagon, was capable of finding Iraq's hidden weapons programs on its own and the US had no foreseeable role for UN inspectors.

The Administration has agreed to permit the Vienna-based International Atomic Energy Agency, which was responsible for conducting inspections of Iraqi nuclear programs, to send a seven-member team to Iraq. The team arrived yesterday to survey a nuclear storage site south-east of Baghdad.

Mr Bush addressed troops at US Central Command in Qatar, where he insisted that Saddam Hussein had been preparing to unleash biological weapons and that the truth about them would emerge.

But he showed a new caution in his language, and omitted his previous confident avowals that the weapons will be found.

However, Mr Bush's aides still predict they will be.

"We're on the look; we'll reveal the truth," Mr Bush said before boarding Air Force One and flying directly up the length of Iraq and over Baghdad.

The decision to view Iraq from nearly 10 kilometres up, rather than from the ground as Britain's Prime Minister, Tony Blair, did last week, underscored US concerns about the obstacles still facing Mr Bush as his Administration struggles to gain its footing as an occupying power.

The Washington Post, The New York Times, Los Angeles Times

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