(VOVworld) – Many European countries have put their security on high alert due to worries of terrorist attacks. A number of suspects have been arrested.

Police investigate a shootout in a street in Verviers, Belgium, on Thursday, Jan. 15, 2015. (Photo:Geert Vanden Wijngaert/ AP)

Belgian authorities say 12 people have been detained in Belgium in an anti-terror sweep following a plot targeting Belgian police on Thursday. Belgium has deployed measures to ensure security in public places nationwide.

British policemen have been on high alert in the face of a terrorist attack. Security has been tightened in areas inhabited by a majority of Jews.

Germany’s domestic intelligence agency (BfV) found evidences of a link between Charlie Hebdo’s terrorists and Islamic extremists in Germany. Leaders of BfV and Germany’s foreign intelligence agency have not yet defined the exact location and time extremists might carry out a terrorist attack in Germany. Police forces will be deployed in railway and metro stations in big cities.

Italian intelligence and police forces on Friday said they have a list of 100 terrorist suspects legally living in Italy. The group tends to support the extremist movement and the Islamic State.