Belgium has highest rate in EU of extremists travelling to Syria
Belgium produces a disproportionate number of extremist fighters for its size.
Figures from October 2015 showed that 470 would-be jihadis had travelled from the country to join Islamic State and other extremist groups in Syria.
Compared to its population of just over 11.2 million, this equates to nearly 42 people per million who made the journey.
According to analysis for i100 by Statista, this means Belgium has the highest rate per capita of all EU countries, coming eighth in the top 15 world countries for which data was available.
A large chunk - around 3,700 of more than 5,000 fighters from EU countries thought to be in Syria - come from four states, according to international security firm The Soufan Group (TSG).
These are France with 1,800, the UK and Germany with 760 each, and Belgium with 470.
A report by TSG late last year suggested that the number of foreign fighters in Syria from Western Europe doubled between June 2014 and late 2015.
There have been particular concerns about the Brussels suburb Molenbeek, where suspected Paris attacker Salah Abdeslam was arrested on Friday.
A string of terror suspects have lived in the area, including Morrocan Ayoub el-Khazzani, who attempted a shooting on a train in France in August 2015, and Mehdi Nemmouche, a French national who killed four people at a Jewish museum in 2014.
In November Belgian interior minister Jan Jambon admitted that authorities did not have control in the suburb.