Prime Minister Tony Blair revealed details of the case against Usama bin Laden on Thursday, saying three hijackers have been "positively identified" as associates and that bin Laden told other cohorts he was preparing a major operation in the United States.
One of the three also played a key role in the 1998 attacks on two U.S. embassies in Africa and last year's bombing of the USS Cole, he said.
Speaking to a special session of Parliament, Blair said there was evidence directly implicating bin Laden and his Al Qaeda network in the Sept. 11 attacks and other incidents. A dossier with some of the evidence was given to lawmakers, but Blair said there was other evidence "of a more direct nature" that could not be disclosed for security reasons.
"We have absolutely no doubt that bin Laden and his network were responsible for the attacks on Sept. 11," he told the hushed session.
Later Blair flew to Russia, arriving in Moscow in the evening, for talks with President Vladimir Putin that Blair said were aimed at strengthening the international coalition against terrorism.
In his speech, the prime minister indicated military action was likely, but gave no hint when it would happen.
"We are now approaching the difficult time when action is taken. It will be difficult, there are no easy options," he said.
In Paris, French Defense Minister Alain Richard said U.S. military retaliation isn't likely for several weeks.
"The decisions to take action haven't been made," Richard said. "Everyone is going to prepare their own means that will be well-adapted for a joint effort. We aren't at the end of that," Richard said.
Blair said three of the 19 hijackers involved in the attacks on New York and Washington had been "positively identified as known associates of bin Laden."
One had played a key role in the 1998 attacks on the American embassies in Kenya and Tanzania, which killed 224 people, and last October's bombing of the USS Cole in Yemen, which killed 17 American sailors, he said.
The individuals were not identified in Blair's speech or in the documents given to Parliament. The documents said one of bin Laden's "closest and most senior associates," also not identified, was responsible for detailed planning of the Sept. 11 attacks.
"Most importantly, one of bin Laden's closest lieutenants has said clearly that he helped with the planning of the 11 September attacks and has admitted the involvement of the Al Qaeda organization," Blair said.
He said intelligence reports show bin Laden told associates shortly before Sept. 11 that he had a major operation against America under preparation, warning cohorts to return to Afghanistan because of the action.
Blair also said bin Laden's involvement was clear in a series of attacks on U.S. targets in recent years.
He said every effort must be made to bring bin Laden to justice and vowed that would be achieved.
The dossier given to Parliament was also posted on the prime minister's Web site.
Blair repeated his earlier warnings to Afghanistan's Taliban regime that it must hand over bin Laden and dismantle his camps in that country or become the enemy of the coalition being formed against terrorism.
"The Taliban must yield them up or become our enemy also," he said.
Blair warned that all Western nations faced the threat of terrorist attack and must unite to form a common defense.
"We will not act for revenge. We will act because for the protection of our people and our way of life, including confidence in our economy, we need to eliminate the threat bin Laden and his terrorism represent," he said.
The prime minister's office has not said how long he will remain in Moscow. Blair said the international coalition was gaining strength daily. "The coalition is strong. Military plans are robust. The humanitarian plans are falling into place," he said.
The British prime minister stressed the importance of matching any future military action with aid to rebuild Afghanistan, ravaged by more than 20 years of war. He expressed strong support for the people of Afghanistan.
Last month's attacks on the World Trade Center and the Pentagon have lent a new intensity to the relationship between Britain and the United States, and Blair is its most fervent advocate. Public reaction was strongly behind Blair and the historic alliance with the United States that Britons call the "special relationship."