New York's police commissioner has said that the internet hosts ideas that could turn westerners into terrorists.

Raymond Kelly referred to the internet as "the new Afghanistan" yesterday.

His comments came as he unveiled a new report called Radicalization in the West: The Home-grown Threat, which charts the possibility of terrorist acts committed by Islamic extremists living in the US.

Because many of those that may pose this "home grown" threat may not have prior criminal records it is hard for police and the Department of Homeland Security to track them down, according to the report.

It stated: "Much different from the Israeli-Palestinian equation, the transformation of a western-based individual to a terrorist is not triggered by oppression, suffering, revenge or desperation."

Such a transformation occurs because the people in question are searching for "an identity and a cause", the report said.

The report uses past terror plots in Madrid, Hamburg and Toronto as case studies.