Ukrainian state nuclear operator Enerhoatom said on August 16 that Russian-based hackers unleashed an hours-long attack on its website but said major problems had been avoided.
It blamed the attack on what it said was a Russian group called "narodnaya kiberarmya," or "popular cyberarmy."
Russian troops launched a full-scale invasion of Ukraine in late February, after eight years of "hybrid warfare" that included disinformation and hacks, in addition to backing for armed separatists in eastern Ukraine following the occupation and annexation of Crimea in 2014.
Enerhoatom has been dragged into the conflict since the early days as Russian troops occupied the Zaporizhzhya nuclear power plant and other nuclear facilities.
"The Russians have launched an unprecedented cyberattack on the official website of Enerhoatom," the company said on its Facebook page.
It called the attack "the most powerful hacking attack" on its site since the invasion started.
It said the Russian group employed "7.25 million bot users who simulated hundreds of million views of the company's homepage for three hours."
But it said the operations of the site were not "significantly" affected and users were unaware of the attempted disruption.
Enerhoatom is central to the current concerns around Zaporizhzhya and Ukrainian and international efforts to safeguard against a nuclear disaster at the facility, including through efforts to allow International Atomic Energy Agency (IAEA) experts to visit the site. The plant has been controlled by Russian forces since March.