Belgium is preparing to invalidate passports and identity cards of its citizens who are believed planning to go and fight for militant organisations in the Middle East in order to prevent the foreign fighters flow.
The government on Friday proposed a law which would take the necessary measures to discourage its citizens from leaving the country to join fight in the Middle East when it passes the Belgian parliament, as the country has been a source of many foreign fighters for the conflict in Syria and Iraq.
ISIS is the main destination for the foreign fighters, and Belgium is one of the largest per capita contributors in western Europe, with more than 300 people of 11 million inhabitants, according to a report by the International Center for the Study of Radicalization (ICSR).
Belgian Justice Minister Koen Geens said authorities would be able to invalidate identity cards of somebody who wants to leave for Syria and Iraq to fight.
"The new law allows us to make leaving Belgian territory with the intention of engaging in terrorist acts a criminal offense," Geens said.
Some of the other European countries, such as Britain and Denmark, have similar measures in practice.
The ICSR report said more than 20,000 foreign fighters have joined the ranks of ISIS in Syria and Iraq by the time the report was released in late 2014, nearly one-fifth of them are residents or nationals of Western European countries.
The report is based on 14 European countries and says the number of foreign fighters from Western Europe has exceeded almost 4,000, double the number in December 2013.
France, the United Kingdom, and Germany have put forth the largest amount of foreign fighters, while Belgium, Denmark and Sweden are the countries most heavily affected by the flow, according to their respective populations, says the ICSR report.
The ICSR data shows France leading the way with an estimated 1,200 fighters, followed by the UK and Germany with 500-600 fighters and the Netherlands with 200-250 fighters.
The total number is 20,730 worldwide, which makes it the largest mobilisation of foreign fighters since World War II, surpassing the Afghanistan conflict of the 1980s.
The report estimates that around 5-10 percent of the foreign fighters have been killed during the clashes, while another 10-30 percent have left the conflict zone, mostly returning their countries or stuck in transit countries.
Europeans travel to neighbouring countries of Iraq and Syria, such as Turkey, for crossing the border.
Some western country media organs have been pointing their fingers at Turkey for accusing the country of letting suspects pass through its borders to join militant groups in its neighbouring countries.
However, Turkey has long been complaining about the lack of intelligence sharing from the countries, mainly France and Germany that rank as the top western countries. whose citizens end up in conflict zones.
Stating Turkey has blocked more than 12,500 people from entering the country and deported more than 1,500 since January, Turkish authorities said the country was doing its part and would continue to do so.