Defence minister Ank Bijleveld has warned that the Netherlands is engaged in a ‘cyber war’ with Russia that threatens to undermine democracy.

Bijleveld’s comments on TV show WNL op Zondag followed the revelation earlier this month that Russian hackers had been caught trying to hack into the wi-fi network of the Organisation for the Prevention of Chemical Weapons (OPCW) in The Hague back in April.

In the most explicit condemnation of Moscow by a cabinet minister so far, Bijleveld said the Russians’ behaviour was ‘dangerous’, adding: ‘We need to stop being naive in this area.’

‘All kinds of attempts are being made to influence our democracy and our day-to-day lives,’ she said.

Russian foreign minister Sergei Lavrov has insisted that the four men, who were intercepted at the Marriott Hotel in The Hague, which backs on to the OPCW building, with a laptop and antenna concealed in the back of their rental car, were on a ‘routine visit’.

They were escorted out of the country on April 13 after being questioned by the MIVD and having their possessions confiscated. A laptop computer indicated they had also visited Kuala Lumpur, where prosecutors are investigating the shooting down of Flight MH17, and Lausanne in Switzerland, home of the World Anti-Doping Agency, which is looking into the extent of drug taking in Russian sport.

The OPCW is carrying out forensic tests in the investigation into the poisoning of the former Russian spy Sergei Skripal and his daughter Yulia in Salisbury, England, on March 4.