The risk of a terrorist attack in the Netherlands remains ‘substantial’ following the tram shooting in Utrecht in March and a number of arrests, counter-terrorism officials say.

The official threat level stands at 4 on a scale of 5, meaning there is a real risk of a terror attack taking place.

The National Co-Ordinator for Counter-Terrorism and Security (NCTV) said that recent documents had emerged indicating that the Islamist movement IS was focusing its efforts on attacks in the west now that it now longer controls any territory in the Middle East.

IS remains ‘capable of mobilising the global jihadist movement,’ said the NCTV, though it added that the group’s capacity to carry out a large-scale attack was diminishing.

‘The number of attacks in the West is low, but the intention remains,’ it said.

Four people died on March 18 when a lone gunman opened fire in a commuter tram near Utrecht’s central station. A 37-year-old man, Gökmen Tanis, was arrested and has confessed to the crime, said police. He claims to have acted alone.