A Russian hacking group has claimed responsibility for taking down several websites belonging to major American airlines, reports said.

According to Bleeping Computer (via Fox Business), Russian hacker group Killnet launched a distributed denial of service (DDoS) attack that caused some U.S. airlines websites to become unavailable for customers and staff alike.

Those who were impacted by the said DDoS attack included Hartsfield-Jackson Atlanta International Airport, Los Angeles International Airport (LAX), O'Hare International Airport in Chicago, and Midway International Airport.

Representatives from Hartsfield-Jackson Atlanta International Airport, LAX, and the Chicago Department of Aviation told Fox that their websites have since returned to normal, adding that operations at the airports themselves were not impacted by the said attack.

The Federal Bureau of Investigation (FBI) and Transportation Security Administration (TSA) have been notified of the said incidents, and investigations looking into the case are currently underway. Fox said the FBI is "aware of the incident" but did not make any other comment. The TSA refused to comment.

Russian attacks

Killnet also previously claimed responsibility for attacks that affected government websites in the United States, specifically Colorado, Kentucky and Mississippi.

The group, which has ramped up its hacking attacks against governments opposing Russia's war against Ukraine, also attacked the U.S. Congress' website in July.

The hacking group's attacks are but part of a bigger plot to stop America from interfering with Russia's war on Ukraine, former Defense Intelligence Agency officer Rebekah Koffler said.

Koffler, author of the book "Putin's Playbook: Russia's Secret Plan to Defeat America," said Russian President Vladimir Putin wants to pressure the U.S. to stop supporting Ukraine with military aid by putting the pressure on everyday Americans.

"Inflicting gradual pain by disrupting the normal functioning of the society is part of the doctrine," Koffler explained. "The goal is to reach the point where people get tired of inconveniences and demand that the U.S. government abandon Ukraine."

But America is not the only target on Russian hacking groups' sights. Earlier reports indicate that some Russian hackers are also looking to launch cyberattacks on crucial facilities belonging to Ukraine and its allies, particularly the Baltic states and Poland.

Per the Ukrainian Ministry of Defense last month, the Kremlin is planning on deploying massive DDoS attacks targeting the said facilities to "try to increase the effect of missile strikes on electricity supply facilities, primarily in the eastern and southern regions of Ukraine."

These cyberattacks, which come years after the attacks that affected Ukraine's energy systems in 2015 and 2016, are meant to "slow down the offensive operations of the Ukrainian Defence Forces."