Terrorists could use drones laden with explosives to carry out an attack, reports the NOS broadcaster on Thursday.

The latest quarterly terror assessment report from the National Coordinator for Security and Counterterrorism (NCTV) – which rates the current threat level as ‘substantial’ – is concerned about copycat drone attacks in the Netherlands.

IS has been using armed drones in battle in Syria and Iraq, and the report says ‘the innovative power of IS is cause for concern’.

The threat level in the Netherlands is rated four out of five, and national coordinator Dick Schoof told NOS that drone sellers and the public should be alert: ‘We need to be careful because with a relatively small explosive on a drone, you can cause damage relatively easily.

‘[People] shouldn’t be paranoid, but if you see a drone above an area where you think “what is it doing there?” you should call the police.’

However, there are currently no signs that terrorists are actively preparing an attack in the Netherlands, according to the three-monthly report.

The Dutch counter terrorism unit said earlier on Thursday that there is a risk that IS may also use child victims in terror attacks. It has published a joint document with security service the AIVD on how IS indoctrinates children, and how they can be helped to reintegrate into society.