Citizens who go abroad to fight for Islamist militant groups are returning “radicalised” and “traumatised”, Dutch officials say.
The Dutch government has raised its terror threat level over fears Dutch citizens are fighting in Syria and returning radicalised.
They fear citizens who have been fighting in the war-torn Middle Eastern country will be traumatised and may be more likely to commit domestic terror acts.
The Netherlands’ National Co-ordinator for Security and Counter-terrorism said in a statement: “The chance of an attack in the Netherlands or against Dutch interests abroad has risen.
“From Europe as a whole, hundreds have made the journey, many of whom are joining local armed groups.
“These Jihadist travellers can return to the Netherlands highly radicalised, traumatised and with a strong desire to commit violence, thus posing a significant threat to this country.”
Counter-terrorism chief Dick Schoof said that nearly 100 people had travelled from the Netherlands to Africa and the Middle East, mainly to Syria.
He said that several fighters had already returned to the Netherlands and were “being monitored”.
The warning comes just two months before hundreds of thousands of people are expected to descend on Amsterdam for mass celebrations for the investiture of Crown Prince Willem-Alexander, as the country’s new king.
The threat level is now rated as substantial, the second-highest level on the four-step scale, just below “critical”.
The government said there were also signs of increasing radicalisation among Dutch youth at home.
Experts have said that political upheavals in North Africa and the Middle East are giving terror networks room to grow.
British Foreign Secretary William Hague recently warned Syria has become the ‘number one’ destination for British extremists wanting to train in guns and explosives.
He has said that there is a danger that fanatics would then return home and carry out terror attacks on UK soil.