Terror threat

France, Belgium Alerted to Possible Arrival of Militant Fighters

 Police have been alerted to the possibility that small groups of extremists have left Syria for France and Belgium with plans to stage attacks, but have not raised threat levels, as authorities work to determine how credible the information is.

Belgian intelligence services sent a note to French counterparts about the possible groups, and it was sent to police and anti-terrorism forces across France on Tuesday, a French security official said Wednesday.

French authorities remain "very cautious" about the information because they receive such notes routinely, the official said, speaking on condition of anonymity to be able to discuss sensitive security information. Belgian officials are cautious too, as the information is believed to be from a single intelligence source and hasn't been confirmed elsewhere.