Powell insists US can demonstrate Saddam's 'deceit'

Secretary of State will detail obstruction to UN but security services remain sceptical over alleged connections to terrorism

Colin Powell will disclose secret communication intercepts and show satellite photographs in his crucial presentation to the United Nations tomorrow in an attempt to prove that Saddam Hussein's government is deceiving UN inspectors.

But the American Secretary of State has admitted he cannot provide the "smoking gun" which proves that Iraq has continued to pursue banned weapons programmes.

General Powell insisted the combined evidence he would put forward – some based on hitherto unreleased photographs, Iraqi communications intercepts and testimony from defectors and captured terrorist suspects – would provide a "straightforward, sober and compelling demonstration" that President Saddam was continuing to engage in deceit and denial, in breach of Iraq's obligations to the UN. Even before General Powell's remarks yesterday, in an article in The Wall Street Journal, senior Iraqi officials dismissed his charges as "fabrication" and demanded a right of reply to rebut them.

General Powell was adamant. "We will not shrink from war," he said, if that was the only way to disarm Iraq. But there appear to be divisions between American and British officials, and also in Washington, about the meaning and significance of the "evidence" which will be unfolded.

For example, Mr Powell's presentation is expected to include satellite photographs of a truck convoy leaving Iraq for Syria before Christmas. The Bush administration maintains that this shows Baghdad moving evidence of its weapons of mass destruction (WMD) programme. But the CIA and MI6 say that while the convoy may be part of regular smuggling runs, there is nothing to prove it contains anything to do with WMD.

There is also concern that the administration is, unquestioningly, using information from Iraqi opposition groups. The intelligence services often find such material unreliable. The Americans are likely to claim the Iraqi secret police, the Mukhabharat, have infiltrated the UN mission and are bugging their offices and vehicles in Baghdad. But security sources say the UN office and fleet of vehicles are regularly "swept" for bugs.

Yet another dossier produced by Downing Street at the weekend claimed 20,000 Iraqi agents were working to foil the UN mission. Their activities include intimidating Iraqi scientists and technicians into not giving information to the inspectors about the alleged WMD programme.

Since President George Bush announced last week that General Powell would address the UN, specialists from the CIA, Pentagon and the Justice Department have been racing to determine what can be declassified. But, as the Secretary of State admits, they will not compare with the impact of the photographs produced in 1962 to proving the Soviet Union was installing missiles in Cuba.

One piece of evidence is likely to be intercepts of phone conversations by Iraqi officials about the work of the UN inspectors. Newsweek magazine says the intercepts, by the National Security Agency, have the Iraqis "saying things like, 'Move that', and 'Don't be reporting that," and "Can you believe they missed that". But it was unclear precisely what was being referred to.

The evidence may still not be enough to persuade sceptics that Washington has proved Iraq's alleged weapons are so great a threat they must be eliminated immediately.

As the diplomatic pace quickens, so does the military build-up. A third aircraft carrier group, led by USS Abraham Lincoln, is within striking distance of Iraq, joining the Constellation and the Harry S Truman. A fourth, USS Theodore Roosevelt, is about to leave Norfolk, Virginia, for the Gulf. By March, the United States will have a force of 150,000 in place, ready to attack.