Emergency alert systems in Russia and Ukraine were hit in cyberattacks overnight, with fake warnings of possible nuclear strikes broadcast to users in both countries.
The systems have since been brought back under control, though much remains unclear about the attacks, including who was responsible.
Phone notifications were sent to millions across Ukraine late Sunday warning of a “nuclear alert,” a “chemical threat” and even “street fights” in Kyiv.
One of the messages was in Russian and included a link to a new Telegram account named “Hitcore,” the logo of which is a metallic eagle emblazoned over the Russian tricolor flag.
Ukraine’s air force said the “air alert” app -- which typically warns of incoming Russian drone and missile attacks -- had been “subjected to hostile interference.”
Air force spokesman Yuri Ignat confirmed the hack to AFP.
A few hours later, Russia’s emergency situations ministry said that a “massive cyberattack” had hit its own application, with “false information” sent to the public.
Several regional social media accounts run by the department sent out messages warning of a imminent nuclear attack on Russia.
For instance, a Telegram message was sent by authorities in the Belgorod border region warning “nuclear warheads ... have been launched at all regions of Russia,” and telling people to “urgently stock up on food for three weeks.”
Ukraine’s air alert app is widely used to warn of Russian missile and drone attacks. It has been downloaded more than 46 million times and has more than 6.7 million daily users, according to developers, Ajax Systems.
Made with support from the digital transformation ministry, it uses air force data to send mobile notifications at the same time country-wide sirens and loudspeakers announce the start of an air raid, urging people to seek shelter.
The alerts blare out day and night in almost all regions of the country.
The hack did not affect other alert systems or government-backed apps that deliver drone and missile warnings.
The app developers temporarily disabled notifications before saying Monday that operations had been restored.
Russia does not have a nationwide air alert system, and beyond border regions does not routinely send warnings to citizens of incoming Ukrainian attacks.
Few Russians use the affected application, run by the ministry of emergency situations.
Some regional authorities, which take information from the ministry, appear to have either automatically posted the spoof message, or circulated the information on their social media channels.
It remains unclear if the attacks were part of the war, carried out by either side, or launched by independent actors or groups.
Ukraine’s Centre for Strategic Communication, a government-backed project set up to counter Russian propaganda and online threats, said “Russians have hacked” the app.
Air force spokesman Ignat told Ukrainian TV: “The Russians did indeed attack this app.”
A pro-Russian group calling itself Hitcore claimed responsibility for the hack of the Ukrainian alert system.
The group launched a Telegram channel shortly before the attack and included a link to the page in the first message it sent through the system.
One post on the page, addressed to Ukraine’s SBU security services and written in Russian said: “Your government is losing” and urged Kyiv’s spies to defect.
Nobody has claimed responsibility for the hack of the Russian system.
Kremlin spokesman Dmitry Peskov told reporters on Monday that the threat of cyberattacks was growing due to the rise of artificial intelligence, adding that Moscow was taking “appropriate measures.”
He did not say who Russia believed was behind the incident.