A total of 148 people passed through Bulgaria last year on their way to Syria to join the ranks of Islamic State (IS).

The figures were presented by Bulgarian MEP Iliana Iotova (S&D) during a discussion entitled “The new face of terror – myth and reality”, which was organised by her on Friday.

The European Parliament estimates that at present around 5000 European citizens are fighting on the side of IS. What is more worrying is that no one knows the exact number of those returning back to Europe.

This statement comes as Belgian media recently revealed that Abdelhamid Abaaoud, the masterminded behind last year's November 13 attacks in Paris, had made an unsuccessful attempt to cross from Greece to Bulgaria on his way to Belgium.

In December 2014, Abaaoud attempted to enter Bulgaria by crossing the Mesta river, but Bulgarian authorities made everything possible to prevent him doing so.

Commenting the terrorist attacks in Paris and Brussels, Iotova said that in order to deal with the threat, efforts should be focused on understanding the genesis of these attacks.

She revealed that one of the important issues discussed by the European Parliament is the radicalisation occurring in prisons.

Iotova is firm that a distinction should be made between the migrant and refugee crisis and terrorism.

As regards the proposed establishment of European border and coast guard to protect EU's external borders, the MEP said that Bulgaria, Romania and Croatia are facing the threat of being turned into a buffer zone for refugees.

She added that a process of division between Schengen members and countries on the periphery is taking place.

According to Iotova, the agreement between the EU and Turkey on the return of migrants is not working well and it might have serious consequences. In her words, the procedure is clumsy and ineffective as only 396 migrants have been returned.