AN apparently coordinated denial-of-service attack organised by pro-Russia hackers rendered the websites of some major US airports unreachable, early Monday, though officials said flights were not affected.

The attacks — in which participants flood targets with junk data — were orchestrated by a shadowy group that calls itself Killnet. On the eve of the attacks the group published a target list on its Telegram channel.

While highly visible and aimed at maximum psychological impact, DDoS attacks are mostly a noisy nuisance, different from hacking that involves breaking into networks and can do serious damage.

“We noticed this morning that the external website was down and our IT and security people are in the process of investigating,” said Andrew Gobeil, a spokesman for Atlanta’s Hartsfield-Jackson International Airport. “There has been no impact on operations.”

Portions of the public-facing side of the Los Angeles International Airport website were also disrupted, spokeswoman Victoria Spilabotte said. “No internal airport systems were compromised and there were no operational disruptions.”

Spilabotte said the airport notified the FBI and the Transportation Security Administration (TSA), and the airport’s information technology team was working to restore all services and investigate the cause.