LVIV, Ukraine -- The largest power producer in Ukraine, which operates four nuclear power plants, last week survived what officials described as the most powerful attack on Ukraine by Russia hackers since the end of February.
According to the Ukrainian nuclear agency, Energoatom, the attack did not cause any harm.
At the same time, Ukrainians are hitting back at Russian digital infrastructure. In Russia, more than 600 online resources including the federal postal service, pension fund, online banking and video conference platforms were affected by Ukrainian hackers in this month, according to a statement by the Ministry of Digital Transformation of Ukraine.
"Cyberspace is a frontline of the 21st century, and victories there are as important as in actual battlefields," Mykhailo Fedorov, the Minister of Digital Transformation of Ukraine, told ABC News.
He's responsible for establishing the so-called "IT army" -- a gathering of more than 230,000 anonymous volunteers who are working together via Telegram, an online messaging platform.
Russia's assault on Ukraine has extended into the virtual domain as well as on real-life battlegrounds. And here the enemy is choosing very sensitive targets that could impact security for Ukraine, Europe and even the world.
But Fedorov said his country's cyber security system was more than efficient.
"None out of over 800 cyberattacks since February 24 caused real losses for the Ukrainian economy, stopped the banking system or damaged critical infrastructure," he said.
Some IT companies in Lviv, one of the biggest hubs for the industry, said they weren't eager to disclose their involvement in the country's digital defense efforts. Some in the Lviv IT community told ABC News it is a matter of a personal choice for members of their staff to join the fight.
Stepan, a 41-year-old member of the IT army, spoke to ABC News but asked not to use his real name because of fears of reprisal.
"On the second or third day of a new phase of Russian aggression I saw the tweet from the minister of digital transformation about the establishment of a Telegram channel, and that was very helpful to figure it out, what exactly to do to help my country," Stepan said.
He said he had no military experience and he spent all his time in front of his computer screen. Now, almost every day, Stepan and the rest of the unofficial Ukrainian IT army are being given clear online instructions explaining top targets and offering software they should use for the coordinated strike.
As a programmer he understands that his input makes sense only as a part of a team effort: "I am not doing a huge amount of work, but in general, when we are acting all together, our input is very useful."
"I just start some applications and I am free for coffee, tracking the process from time to time -- maybe some new targets emerged," he said, adding that the IT warriors were not staying in front of their computers every moment of the day.
He added, "I am always analyzing and searching for some additional information. Why this particular target is important, who are those people to be affected by our interference."
When asked if he worried about the impact of his efforts on everyday Russians, he said that "it is not the time for that, as I do not see any changes in Russian society during these months -- sure, it is not a matter of some rapid shifts in their consciousness. That is why we just have to keep on doing what we are doing."
The volunteer-based IT army's mission now is to hold the digital frontline of Ukraine while the regular cyber forces are still in the process of assembling, Fedorov, the minister, said. The country is countering Russian cyber-attacks on a daily basis, he said.
Russia is weaker after at least 40 cybersecurity companies announced their withdrawal from the Russian market and suspended service for Russian clients, Fedorov said.
"As many software or hardware solutions just cannot be replaced by Russian-owned technologies, it takes time to develop their own solutions," he said.
The minister also said he was is counting on international support for Ukraine, asking the international tech sector to share the newest cyber solutions and offer service and equipment, which can help Ukraine.
"We are showing Russia that tech is a future, and tech will win over large manpower and outdated tanks," he said.
As a member of the IT army, Stepan said he believed that he is weakening the Russian economy and its sponsorship of the terror on Ukrainian soil. And he is not the only member of his family who is involved into the struggle.
"Together with my wife, who is also a volunteer, but in a different way, we are actively waiting for this war to end," he said.