A Ryanair airplane in seen on the runway at Adolfo Suarez Madrid Barajas Airport passing by the air traffic control tower.
London CNN  — 

Europe’s air traffic control authority says it has been battling an ongoing attack, claimed by pro-Russian hackers, since Wednesday.

There hasn’t been any impact on flights, though access to its website has been affected, according to the European Organization for the Safety of Air Navigation, or Eurocontrol.

“The attack is causing interruptions to the website and web availability,” a Eurocontrol spokesperson said in a statement. “There has been no impact on European aviation.”

The International Air Transport Association also said air traffic was operating normally.

“There has been no inconvenience to commercial air traffic, no disruption and no delays because of the cyberattack,” the industry group said.

Eurocontrol is an inter-governmental organization that helps manage Europe’s airspace and ensure the smooth operation of tens of thousands of flights every day by sharing information between commercial and military actors.

The group has 41 member states, including countries outside the European Union such as the United Kingdom and Israel, and is headquartered in Brussels.

Cyber warfare

Pro-Russian hackers have claimed responsibility for a number of cyberattacks on institutions in Europe since Moscow launched its full-scale invasion of Ukraine in February 2022. European countries have provided military assistance to Ukraine and imposed a raft of sanctions on Russia aimed at crippling its ability to wage war.

Last year, for example, Lithuania’s defense ministry said a prolonged cyberattack hit websites of government agencies and private firms in the country.

A Russian-speaking hacking group, known as Killnet, claimed responsibility for at least some of the hacks, saying they were in retaliation for Lithuania blocking the shipment of some goods to the Russian enclave of Kaliningrad, located between Lithuania and Poland.

Denmark’s Center for Cybersecurity raised its threat level for the country in March, noting “high activity from pro-Russian activist hacker groups against NATO countries, including Denmark,” and the groups’ “increased capabilities.”

“It is likely that the pro-Russian groups will stay motivated to go after targets in Denmark and the West, as long as the current crisis between Russia and the West lasts,” the center said in a statement.

Distributed denial-of-service, or DDoS, attacks — which flood websites with phony traffic to knock them offline — have been a common tool, according to the Danish authority. Although DDoS attacks are disruptive and attract attention, they “leave no permanent of destructive consequences to the victims’ systems,” it said.

Some hacking campaigns targeting European entities are believed to have ties to Russia’s military.

Microsoft told customers in March that Russian military-linked hackers targeted — and, in some cases, successfully infiltrated — the networks of European military, energy and transport organizations in an apparent spying campaign that went undetected for months.

In a separate report published last month, the company said its analysts had detected Russian cyber “threat activity” against organizations in at least 17 European nations between January and the middle of February. Governments were “the most targeted,” it said.

— Sean Lyngaas contributed reporting.