Belgian soldiers patrol outside the European Union headquarters in Brussels, capital of Belgium, on Jan. 19, 2015. (Xinhua/Zhou Lei)

BRUSSELS, Nov. 14 (Xinhua) -- Europe must be prepared to cope with a "wave of jihadists" returning from Syria, as situations keep escalating in the regions controlled by the Islamic State (IS), warned Belgian interior minister Jan Jambon.

"We can see that IS is under pressure in (the Syrian cities of) Raqqa and Mosul, Belgian jihadist fighters will either stay there to help the IS defence, or they will be sent back (to Europe)," Jambon told an interview with broadcaster RTBF aired on Sunday.

Jambon revealed that among all the Belgian nationals who left to join the IS in Syria, 117 had returned, adding that half of these people are now in prison, and the other half under surveillance.

Moreover, Jambon warned that Europe as a whole is facing a more severe threat, saying "Apart from the 200 Belgians, 3,000 to 5,000 European citizens are over there."

Nonetheless, the minister believes that Belgium is safer than before the terror attacks in Paris last November and the bombings in Brussels in March, as a result of tight security measures. Both attacks were plotted in Brussels.

"All the intelligence services are keeping an eye on the situation and exchange information," he said. "If this wave does arrive, we must be ready."