At least 10 planned terrorist attacks in Europe were discovered and halted by western security services in 2023, the Dutch security service AIVD said on Tuesday.

People were arrested in the Netherlands in four of the foiled attacks, which ranged from concrete preparations to target a specific event or building, to random knifing incidents.  

The claim is made in the agency’s annual report, which said jihadist movements remain the biggest terrorist threat to the Netherlands. And while there have been fewer attacks in Europe than in recent years, “certain events” can lead to violence, the AIVD said. 

Two such trigger events – the war in Gaza and Koran burning by far-right groups – did take place last year and led terrorist organisations such as al-Qaida and IS to call for attacks in the west.

“The grim picture painted by the AIVD last year has worsened in many ways,” the AIVD said. “National threats are increasingly linked to international developments. There have been two major conflicts, numerous terrorist attack plots foiled in the Netherlands and abroad, and the Netherlands is targeted daily in cyber attacks.”

The threat level in the Netherlands was raised from three to four, or substantial, in mid-December. 

“There is a reason why this period has been described as ‘the grey zone’ between war and peace, AIVD director Erik Akerboom said. “This poses great risks to the Netherlands, which owes much of its peace and prosperity to international trade and to a rules-based world order.”

The agency also raised its concerns about the rise in anti-institutional protests and the willingness of some so-called sovereign citizens to use violence. The military security service MIVD gave a similar warning earlier this month. 

Akerboom also said the service made a 70% rise in requests to use “special investigative methods” last year, such as hacking and internet taps, but did not say how many requests had been made. The report did say 1,117 bugs, telephone and internet taps had been placed by the agency in 2023. 

Russia and China too remain a threat to the Netherlands, particularly through industrial espionage and, in the case of Russia, spreading misinformation.