Denver International Airport website was targeted in apparent pro-Russia hacking attack

The websites for several major U.S. airports are back online after pro-Russian hackers say they knocked more than a dozen of them offline. Denver International Airport was among the airports that was targeted on Monday but its website didn't go down. No flights on Tuesday are affected.

The hack comes a week after the State of Colorado website was targeted by hackers. The homepage was down for two days as part of that incident.

The cyber attacks consist primarily of hackers flooding targets with junk data. They were orchestrated by a shadowy group that calls itself Killnet.

While the attacks are on targets frequently used by the public, they are mostly just an inconvenience. They differ from hacking that involves breaking into networks.

Officials from Denver International Airport said the attack they experienced began at approximately 11 a.m. and it was an attempt to overwhelm their website so it would become unavailable to the public. They said the attacks were not impactful and no operations were impacted. FlyDenver.com, the airport's website, remains online.

MORE FROM CBSNEWS.COM: U.S. airport websites knocked offline in apparent pro-Russia hacking attack