Sources: Security threat level for London raised to 'severe' - CNN.com

Sources: Security threat level for London raised to 'severe' - CNN.com: "London (CNN) -- New information has emerged from an intelligence operation about the possibility of an attack being planned in or near London, with subway stations and airports of particular concern to officials, a British security source told CNN Thursday.

CNN understands that the intelligence operation concerns a possible Mumbai-style attack, the source said.

The action is not connected to terrorism arrests last month in Stoke, Cardiff and London, the source said."

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