Europe’s air-traffic agency, Eurocontrol, has become the latest target of pro-Russian hackers aiming to disrupt air travel. The agency confirmed on Friday that its website had been “under attack” since April 19, with “pro-Russian hackers” claiming responsibility for the disruption.

Impact on communications not aviation

Despite the attack causing interruptions to the website and web availability, aa spokesperson assured that there had been no impact on European aviation. The agency coordinates commercial traffic among 41 states, including the EU and their national air-traffic control entities. The outage affected the agency’s communication systems, forcing some smaller airlines to rely on older technology, such as fax-era backup systems, to manage flight schedules.

While the spokesperson declined to answer specific questions about the incident, they confirmed that the attack had not put air-traffic safety at risk. However, Eurocontrol’s internal and external communication was affected, requiring the organization’s 2,000 employees to use alternative commercial communication tools.

Previous attacks by Pro-Russian hackers

The pro-Kremlin group Killnet has previously claimed responsibility for large-scale distributed-denial-of-service (DDoS) attacks, such as knocking more than a dozen US airports’ websites offline last October and downing German airport websites in February. These attacks require little technical expertise and are relatively easy to execute, making them attractive to hacktivists looking to stage publicity stunts.

Killnet, a “relatively-unsophisticated” hacktivist group supporting Russia during the Ukraine war, has been encouraging its affiliates to launch similar DDoS attacks against US and European critical infrastructure websites. Recently, a DDoS attack shut down nine Danish hospitals’ websites for a few hours in February but did not have any life-threatening impact on operations or digital infrastructure.