Three leading Dutch banks and the nation's tax service have been hit by powerful cyberattacks over the past several days that have blocked access to websites and online banking services.
Dutch media reported on January 29 that ING, ABN Amro, and Rabobank had been targeted in a total of seven major attacks over the last week. The Dutch Revenue Service was also attacked, and its site was down briefly on January 29.
Officials at all four institutions said no personal data or client details were compromised.
It was not clear who was responsible for the attacks.
Dutch antiterrorism chief Dick Schoof declined to comment on speculation that the attack could have been connected to recent media reports that Dutch intelligence services provided "crucial intelligence" to the United States in its investigation into what U.S. intelligence agencies have concluded was a Russian hacking-and-influence campaign to meddle in the 2016 U.S. presidential election.
The Dutch daily Volkskrant reported that Dutch security agents had accessed computers used by a Russian hacking group known as Cozy Bear in 2014 and monitored it for at least one year.