The United States has "very convincing evidence" that Iraq maintains an extensive weapons programme, a top official has said.

The statement by US undersecretary of state John Bolton comes only days before UN weapons inspectors present their first formal report to the Security Council.

Mr Bolton told a Tokyo news conference such weapons included long-range ballistic missiles banned for Iraq since the Gulf War, Reuters news agency reported.

We know from multiple sources that Saddam has ordered any scientist who cooperates during interviews will be killed Paul Wolfowitz US Deputy Defence Secretary

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Earlier, an Iraqi opposition group claimed it has evidence that elite Iraqi army units have been equipped with protective suits and drugs to defend them against nerve gas or other chemical weapons.

On a political level, the US and European Union have been urged to "cool off" after differences emerged over military action against Iraq.

And the Malaysian leader, Mahathir Mohammed, has warned of "terrorist" backlash if the US did attack on Iraq.

Scientists' 'dilemma'

In the 12 years since the end of Gulf War, Iraq had been engaging in "a systematic campaign of denial and deception in an effort to conceal its weapons of mass destruction from the inspectors", Mr Bolton said, at the end a tour of Asia.

He said that the US would make a case about Iraq's violations "at an appropriate time and in an appropriate way."

His statement came hard on the heels of a key speech by US Deputy Defence Secretary Paul Wolfowitz, who gave a long list of instances in which, he said, Iraq was still lying about and concealing its weapons programmes.

KEY DATES

27 Jan - First full report on inspections presented to UN 29 Jan - UN discusses report 31 Jan - Bush meets Blair 15 Feb - Anti-war protests across Europe 27 Mar - Blix submits new report to UN

Next steps in full

"Today we know from multiple sources that Saddam has ordered any scientist who cooperates during interviews [with the UN inspectors] will be killed, as well as their families," Mr Wolfowitz said.

Earlier in Baghdad, Iraqi officials had said they were encouraging scientists to speak to the UN, but six had so far resisted efforts to question them alone.

A White House spokesman on Friday said any refusal to allow weapons inspectors to conduct private interviews with Iraqi scientists was "unacceptable".

UN inspectors have been back in Iraq for two months, searching for evidence of nuclear, chemical and biological weapons in Iraq, which denies possessing them.

Visits continued on Friday, but a UN laboratory analysing collected samples said no evidence had yet emerged of a nuclear weapons programme.

Iraq itself says it expects the weapons inspectors' report - due to be presented on 27 January - to be neither white, nor black.

'Very negative'

After further signs of division emerged among UN Security Council members about the prospect of military action, Russia and Germany made a joint call for more diplomatic efforts to resolve the Iraqi crisis peacefully.

President Vladimir Putin and Chancellor Gerhard Schroeder said they had agreed that all political options must be exhausted and stressed that weapons inspectors must be allowed the time they need to complete their mission.

The EU's foreign policy chief Javier Solana said a "rift" between the EU and US would a "very, very negative thing".

"I think we have to cool off a little bit on statements, etc to look at the situation with rational eyes," he told reporters in Athens after talks with Russian Foreign Minister Igor Ivanov.

"We have a profound friendship with the US and we have to do our utmost to maintain this relationship."