Norway fears extremists'' attack

Norwegian armed police took high security measures at high-risk locations including airports and train stations, after the police's intelligence unit said on Thursday it received credible information that an attack might take place in the country in coming days.

"We have received information that a group of fighters have left Syria with the aim of carrying out terror attack in the West and Norway was specifically mentioned among their targets," Jon Fitje Hoffmann, the chief analyst for the Police Security Service told TV2 in an interview on Friday.

No specific information about fighters'' connection to Norway or the country''s Muslim community was given by Hoffmann.

The police said earlier that 50 Norway-based militants who have travelled to Syria after the civil war started and gained combat experience in conflicts around the globe, are currently seen as the biggest threat to the Nordics.

NATO member Norway has been working to clamp down on militant activity. In May it arrested three people suspected of aiding the Islamic State in Iraq and the Levant, an al Qaeda offshoot fighting in Iraq and Syria that now styles itself Islamic State.

Neighboring Denmark and Sweden had also warned that people travelling to Syria and receiving combat training were posing an increasing security risk.