From al-Guardian:

For the first time since the 1976 Montreal games, [Olympic] athletes from "high-risk" countries, including Britain, will be accompanied by armed guards.

The Olympics join a long list of potential targets for Osama bin Laden's al-Qaida or one of its satellite groups: the Nato summit in Istanbul, the US presidential elections, Britain at any time.

Al-Qaida and its sympathisers will be emboldened by the impact of what is now assumed to be its first attack in western Europe...

If it was al-Qaida, Spain will have become the first country "to have a prime minister owing his position to Bin Laden," said Jonathan Eyal, the director of studies at the London-based Royal United Services Institute...

Rohan Gunaratna, author of Inside al-Qaida, one of the most detailed accounts of the organisation to be published, predicted that al-Qaida would be intent on launching an attack in the US during the presidential election campaign. "They realise it will be difficult but they will try to do it. A group like al-Qaida has the ability to infiltrate," he said...

Mr Gunaratna said: "The al-Qaida strategy is to isolate the US because the US has, by building a coalition, weakened al-Qaida. One way to isolate the US is to target the countries helping the US. You can see they have attacked the British in Turkey, the French in Karachi, the Australians in Bali and the Italians in Iraq."