The Bristol airport in the UK recently recovered from a ransomware attack which prompted the airport to take flight information screens offline in an effort to keep the attack contained.

This action was taken on Friday and the screens were back in operation by Sunday in “key locations” including departures and arrivals while officials are working to restore the entire site, an airport spokesperson told the BBC.

“We believe there was an online attempt to target part of our administrative systems and that required us to take a number of applications offline as a precautionary measure, including the one that provides our data for flight information screens,” Spokesman James Gore told the publication.

“That was done to contain the problem and avoid any further impact on more critical systems.”

Gore added that they believe the attack was a speculative attempt and not a targeted attack and that neither flights, security, nor passenger safety were at risk as a result of the attack.  The airport was forced to resort to contingency measures in which flight information was handwritten on whiteboards and sheets of paper.

Cyberattacks against airports aren’t new as an attack took place this past March at the Hartsfield-Jackson Atlanta International Airport and shut down its free WiFi network and disabled some of its website’s functionalities after a citywide ransomware attack took down the local government’s network.

Two Ukrainian airports were also affected by a Petya variant in 2017.