The security threat level in the Netherlands remains high with the overseas Jihadist conflict zones, notably Syria, being the main cause of concern.The National Coordinator for Security and Counterterrorism (NCTV) is concerned about the likely action of returnee jihadists from fighting on behalf of Syrian opposition forces, local media reported on Monday.Around 100 Dutch nationals have so far gone to Syria, of whom about 70 remain in the country, according to the NCTV figures.Some 20 have since returned to the Netherlands and 10 have been killed. 11 Dutch nationals have had their passports cancelled or refused because they intended to go to Syria to take part in the fighting.All Dutch nationals known to be involved in the fighting in Syria have lost their social benefits rights.