So far 33 servers in several different Dutch data farms have been taken off line as part of what is set to be the biggest ever international operation against ransomware cyber crime.

The servers, around one-third of the total seized in the operation so far, were being used to host programmes allowing blackmailers to break into company websites and hold them to ransom around the world.

In total, 14 countries were involved in Operation Endgame to take down five botnets or networks of computers infected with software that gave the hackers access. The operation was coordinated by European policing agency Europol in The Hague.

Dutch police estimate the crooks got away with €69 million in cryptocurrency from companies and private individuals who were being held to ransom using the networks.

Operation Endgame is not yet over and more botnets are now in the spotlight, Dutch police said.

Four people have so far been arrested and eight others added to international most wanted lists for their involvement in serious cybercrime activities.