Nato said yesterday the US had provided "clear and compelling" evidence linking the terrorists who attacked America both with Osama bin Laden's al-Qa'ida network and the Taliban regime in Afghanistan.

After a 40-minute intelligence report at Nato headquarters in Brussels, the alliance declared itself satisfied that the attacks came from abroad - the only condition needed to activate its Article 5 collective security agreement. It remained unclear what use, if any, the US will make of Nato's offer of support. But the briefing increased the international pressure on the Taliban by demonstrating that the US is confident enough of its case against Afghanistan to outline it to its allies. Whether its claims would stand up in a court of law remains doubtful, however. The evidence, presented by Frank Taylor, the US State Department's co-ordinator for counter-terrorism, was described by one source as powerful and convincing but circumstantial. The Russian President, Vladimir Putin, meanwhile, told a news conference during a visit to Belgium: "Russia's special services do not need any additional proof to participate in the struggle against terror acts", as he gave strong support to the US-led coalition. The alliance's ambassadors were given no direct documentation or intercepted communication proving that Mr bin Laden ordered the attacks. As one source put it: "This is not the type of briefing where they come with a copy of a bank transfer or a ticket invoice." Instead, Mr Taylor reconstructed the events of 11 September and the efforts of the massive FBI investigation to link those who took part in the terrorist attack, through their contacts, to the al-Qa'ida network and to the Taliban. After the classified briefing, the Nato secretary general, Lord Robertson of Port Ellen, said: "It is clear that all roads lead to al-Qa'ida and pinpoint Osama bin Laden as being involved ... The facts are clear and compelling. The information presented points conclusively to an al-Qa'ida role in the 11 September attacks. We know that the individuals who carried out these attacks were part of the worldwide terrorist network of al-Qa'ida, headed by Osama bin Laden and his key lieutenants and protected by the Taliban."