The sudden increase in the number of pages on the Internet extremist recruitment facilitates the work of Al Qaeda, said the president of Interpol, Ronald Noble. "The threat is global, is virtual and is here, at our doors," he warned.

In a speech to police chiefs on Tuesday in Paris, Noble explained that in 1998 there were only 12 pages of this type, while in 2006 there were about 4,500.

Alexander Meleagrou-Hitchens, from the Center for the Study of Radicalization, told the BBC that this number is now much higher. "Only in English there are many thousands," said the expert, who believes that governments take the proliferation of these pages as an unstoppable process.

In August, the head of the British internal security service (MI5), Jonathan Evans, expressed concern about the influence of Yemeni Muslim cleric Anwar al Awlaki, who has uploaded more than 5,000 recordings of his sermons to the YouTube video portal. Al Awlaki is related to the attempted attack on Christmas Day 2009 against a flight between Netherlands and the United States.

In addition, Noble said that the Internet is an obstacle to the fight against radical thought because many of these propaganda activities do not constitute a crime. Increasingly, Noble went on, the recruits are younger, more vulnerable and belong to the middle class.