False alerts began reaching users of the Ukrainian service at 22:47 Kyiv time on Sunday, according to BBC Russian. The first message announced a red-level air-raid alert across the entire country. A minute later, a notification arrived in Russian: "Hi! A nuclear alert is about to happen all over Ukraine. Don't worry, an Oreshnik is flying." Residents of Kyiv and other cities also received warnings of a radiation contamination threat, a chemical attack and street fighting, with instructions to stay indoors.
Ukraine's Air Force said the app had been "subjected to enemy influence" and denied any radiation threat. The State Emergency Service of Ukraine said the national alert system was operating normally and that all signals are relayed to regional administrations and street-level warning systems.
The app's developers confirmed the breach and temporarily disabled push notifications. They said the app does not store users' personal data, so there was no threat to them. The service began gradually restoring operations overnight.
At around 2 a.m. Moscow time, Russia's Ministry of Emergency Situations (MChS) reported a cyberattack on its own mobile app. The ministry said that as a result of a "massive cyberattack," unknown parties sent users fake information. According to The Moscow Times, the notifications spoke of "nuclear warheads launched at all regions," carried by P1-SUN vehicles — the name of an FPV interceptor drone made by the Ukrainian company SkyFall. Residents were urged to stock up on three weeks' worth of food and hide in basements.
Similar messages were then sent by channels belonging to regional MChS offices on the MAX messenger — for St Petersburg and the Moscow, Belgorod, Nizhny Novgorod, Sverdlovsk, Tyumen and other regions. The Telegram channel of the Belgorod region's operational headquarters published a similar warning.
The MChS said it was working to fix the vulnerability and restore the app's operation, and that the public alert system was functioning normally. It said information is disseminated via sirens, loudspeakers, SMS messages, and television and radio broadcasts.
According to the Ukrainian outlet UNN, the partisan movement Atesh claimed responsibility for hacking the Russian app. The BBC said it could not confirm the authenticity of a screenshot published by the movement.
The cyberattacks coincided with the end of a silence regime in the Russian-occupied town of Alyoshky in the Kherson region. The regime had been in effect since October 27 to allow a humanitarian mission and the evacuation of local residents. Dmytro Lubinets, the Ukrainian parliament's human rights commissioner, said both sides observed their obligations during the period, which allowed humanitarian aid to be delivered and helped residents leave the town. He said the work was carried out jointly with Russian human rights commissioner Yana Lantratova, coordinated by US First Lady Melania Trump. Melania Trump said about 800 people had been evacuated from Alyoshky.