AMSTERDAM, April 23 (Reuters) - The Netherlands warned on Wednesday militants returning from Syria posed a security threat to Europe and said two Dutch citizens had carried out suicide attacks in Syria and Iraq in the past six months and about 100 had fought in Syria in 2013.
With the Syrian conflict entering its fourth year, governments across Europe are growing increasingly concerned about the number of their nationals heading to Syria to fight.
Interior Minister Ronald Plasterk, speaking at the launch of the Dutch intelligence agency's annual report, said one Dutch national had travelled from Syria to Iraq before carrying out an attack with a bomb in a rucksack. The other carried out a car bomb attack in Syria. Plasterk declined to identify the attackers or give details of casualties in the suicide blasts.
The number of Dutch citizens leaving for Syria to fight on the side of Islamic militants battling to overthrow President Bashar al-Assad had grown sharply in 2013, Plasterk wrote in the introduction to the report.
"The consequence is that at the end of 2013, dozens of Dutch jihadists have become habituated to extreme violence and have become radicalised in their intolerant and violent ideological orientation," the agency said.
The General Information and Security Service said about 100 Dutch citizens had travelled to Syria in 2013, joining the Islamist militant groups Islamic State in Iraq and the Levant and Jabhat al-Nusra. About 20 had returned.
On Tuesday, France unveiled policies aimed at stopping its citizens joining the Syrian civil war and preventing young French Muslims becoming radicalised and posing a threat to their home country.
French nationals who return from Syria could automatically face charges of being part of a terrorist organisation, while minors would be prevented from leaving France without parental consent.
(Reporting By Thomas Escritt; Editing by Janet Lawrence)