(WTVO) — Several U.S. airports have reportedly been hacked by an attacker within the Russian Federation.

The systems targeted do not handle air traffic control or internal airline communication and coordination, but have instead target public facing domains which report airport delays and congestion, jamming up systems.

The pro-Russian hacking group “Killnet” is allegedly behind the cyberattack, though it is not clear if the Russian government is involved.

New York’s Laguardia, LAX and Chicago O’Hare were among those to report website disruptions. Those are all back up and running.

“Killnet” has been active since the start of Russia’s invasion of Ukraine, according to cybersecurity sexperts. The group has previously taken credit for taking down some government websites in the U.S.