Islamic State (ISIS) flag
Islamic State (ISIS) flag Reuters

Belgian authorities on Wednesday charged two Kosovars and a Serb with terrorist offenses over suspicions they helped recruit jihadists for Syria and raised funds for the Islamic State (ISIS) group.

A counter-terrorism judge kept in custody three of the eight people who were detained during raids across Belgium on Tuesday but released the remainder after questioning, federal prosecutors said.

"They were charged with participation in the activities of a terrorist group," the prosecutor's office said in a statement.

It identified them as Egzona K., a 23-year-old Serb, Kastriot M., a 23-year-old Kosovar, and Mahid D., a 27-year-old Kosovar.

Following the raids on Tuesday, the prosecutor's office said those arrested were "suspected to be involved with recruiting people to leave for Syria and with having financially supported IS."

Belgium is the EU country with the highest per capita number of fighters who have joined jihad in Syria and Iraq, a figure estimated at 465.

The country has been on high alert since suicide bombers struck Brussels airport and a metro station near the European Union headquarters on March 22, killing 32 people.

Those attacks were claimed by ISIS, which controls parts of Iraq and Syria and has claimed numerous terror strikes in Europe over the last year, including attacks in Paris which left 130 people dead.

In October, two police officers were stabbed in the Belgian capital, in what local authorities investigated as a terrorist attack.

The attack came two months after two policewomen were wounded in Charleroi by a machete-wielding man who shouted "Allahu Akbar", an attack claimed by ISIS.

Radicalization is a phenomenon that has plagued not just Belgium but other countries in Europe as well, including Germany, France and Austria – to name a few.

AFP contributed to this report.