The November 13 massacres in Paris were just a preliminary strike.

This was the claim of Abdelhamid Abaaoud, the Belgian-born terrorist who is thought to have organised the Paris attacks, before he was killed in a police raid on his hideout in Saint-Denis, northern Paris.

The statement by Abaaoud was reported last week in conservative weekly Valeurs Actuelles, which quoted sources in SDAT, the police anti-terror unit.

Apparently, Abaaoud warned on November 15 that the Daesh cells in Paris would "do even worse" during the Christmas and New Year holidays. He mentioned targets including "areas near Jewish places", public transport and schools. "We are everywhere," he boasted.

Police authorities believe that Abaaoud was telling the truth, and that there are indeed many dormant Daesh cells both in France and Belgium.

Daesh may have as many as 10,000 active sympathisers and contacts in France alone, as well as 1,500 trained fighters.

Salah Abdeslam, another Belgian-born jihadist and the operational commander on November 13, managed to escape. It is not clear whether he left France for the Daesh-controlled areas in Syria, or stayed in Europe.

Police sources have confirmed that potential terrorists may have entered the EU as "refugees" from Syria. According to Frontex, the EU agency in charge of border controls, no less than 710,000 people, chiefly young men, have been admitted in the nine first months of 2015.

Another concern is the growing number of French converts to Islam who join Daesh. Last year, around 4,000 French citizens converted, mostly under the aegis of radical mosques.

Synagogues and other Jewish sites remain under heavy military protection.

At a ceremony last week to commemorate the victims of the attacks, Jewish singer Natalie Dessay sung Perlimpinpin by French songwriter Barbara. President Francois Hollande said at the event: "We will sing even more, continue going to concerts and stadiums… The terrorists will fail."