France detained a dozen suspects believed to have aided the gunmen who carried out the slaughter in Paris a week ago, while separate raids in Belgium and Germany kept nerves on edge across Europe amid a heightened terror threat.

French police said Friday they had detained eight men and four women overnight across the Paris region. A police officer close to the matter said all were suspected of having provided support to the gunmen ahead of the attacks at the satirical magazine Charlie Hebdo and a kosher supermarket.

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