Ukraine has so far managed to fend off Russia's cyber onslaught and has locked down its electrical grid and nuclear power systems against such attacks, said a top government official there, who claimed a global volunteer army is assisting Kyiv on the digital front.
"All nuclear power stations are well protected" from cyber incursions, Victor Zhora, deputy chairman of the State Service of Special Communications and Information Protection in Kyiv, said Friday in a video call with reporters. "I want to assure everybody that they are completely safe" from attacks through the internet.
But, he warned, these critical infrastructure systems remain vulnerable to physical attacks from the Russian military - from shelling, rocket fire and bombings.
"These are much more serious than attacking them with cyberweapons," he said.
Zhora's comments followed Russia's seizure hours earlier of Europe's largest nuclear power facility, the Zaporizhzhia plant in southeastern Ukraine. The shelling of a building on the premises led to a fire, triggering widespread fear that any significant damage could precipitate a radiological disaster. The International Atomic Energy Agency has said that officials have not detected any leaks.
Ukraine was the target of Russian cyberattacks in the lead-up to last month's invasion, incidents that wiped data maintained by government agencies and defaced some of their websites with threatening messages - what Zhora characterized as part of the Kremlin's "hybrid" war.
But those efforts have not cut off Ukraine from the world or prevented it from waging a cunning information war, marked by emotional appeals from President Volodymyr Zelensky to the international community and profuse imagery on social media depicting death and destruction caused by Russia's bombardment.
Zhora said that an estimated 400,000 IT specialists, software developers and students from around the world have volunteered "to defend our country in cyberspace." They are using unique methods to reach the Russian people in a bid to turn public opinion against the war, he said.
Some international volunteers, along with Ukrainian citizens, are sending "messages, videos, pictures of dead Russian soldiers ... to Russian mothers" to "raise the movement inside Russia that all aggressive actions of the Russian government should be stopped."
Since Sunday, Ukraine's Ministry of Internal Affairs, too, has posted a steady stream of graphic images showing Russian soldiers' corpses that have been burned, mangled in wreckage or abandoned in snow - inviting Russians to examine them to determine whether they feature a missing loved one.
The aim, Zhora said, is "to bring truth and make people understand that real war is happening here." Russia has imposed severe restrictions on media coverage of the war.
The volunteers also are targeting Russian military and government systems, said Zhora, though he was not specific about which networks and what they were doing.
"Russia thinks that only super countries, super states can provide these attacks," he said. "But more than 400,000 people are united in this IT army. We call it cyber resistance. And [they're doing] everything possible to protect our land, our cyberspace, our networks."
Ukraine is anticipating that Russia might escalate in cyberspace. "But now our IT community, our cybersecurity community is united," Zhora said. "We showed that Ukraine has enough capacities to resist ... cyber aggression."
The Kyiv government is focused on shoring up the defense of its own systems, its electric, nuclear, transportation and other networks, he said.
Internet outages have been reported in cities such as Mariupol in the southeast and Sumy in the northeast. But he said those are the result of "constant fire from Russian military forces." He added: "Fiber optic lines are damaged. Traffic exchange points are damaged. All the infrastructure of [internet providers], mobile operators, their base stations, can be damaged in these regions."
He expressed gratitude for the assistance coming from the West, including the delivery of Starlink satellite internet systems - sent by Tesla CEO Elon Musk, who he said is helping Ukraine remain online and communicating with the world.
Microsoft said Friday it had acted to counter malicious Russian cyber efforts aimed at more than 20 Ukrainian government, IT and financial sector organizations, as well as to stop cyberattacks targeting several civilian sites.
While completely air-gapping any computer system is not usually feasible, Ukraine does appear to have "done as best they can to isolate" critical systems from the internet, said Tim Roxey, a nuclear engineer and cybersecurity expert.
To win the cyberwar, Zhora said, the shooting war must end.
"Cyberwar can be ended with the end of conventional war, and we will do everything to make this moment closer."
The White House is not advocating for regime change in Russia, President Joe Biden's spokesperson said on Friday after a U.S. senator advocated for
Russians to assassinate President Vladimir Putin.
"We are not advocating for killing the leader of a foreign country or regime change. That is not the policy of the United States," White House spokesperson Jen Psaki told reporters.
U.S. Senator Lindsey Graham, a Republican from South Carolina, called for someone in Russia to "take this guy out," referring to Putin.