False warnings of nuclear danger, radiation and street fighting reached Ukrainians through an emergency alert application late Sunday, prompting authorities to reassure residents that the threats were baseless. Russia reported a hack of its own emergency app hours later. Whether the incidents were connected was not immediately clear.
The Ukrainian messages began arriving around 10:45 p.m. Kyiv time and told residents to remain indoors because of radiation, chemical dangers and fighting in the streets. One Russian-language notification claimed that a nuclear alert covered all of Ukraine and referred to Oreshnik, Russia’s nuclear-capable hypersonic missile. The messages appeared on a service that millions of Ukrainians depend on for warnings of approaching Russian missiles and drones.
Ukraine’s Air Force said the Air Alert app had probably been compromised by the enemy and confirmed there was no radiation threat. The app’s developers said unauthorized outsiders had interfered with its operation, leading them to suspend the service temporarily. They subsequently described the incident as a cyberattack and said service was being restored gradually while the team introduced additional protections.
Ukrainian media reported that the notifications reached users nationwide. Authorities in the western Lviv region said some public sirens and loudspeakers also broadcast a radiation warning. Many Ukrainians responded with online jokes and memes, mocking both the messages’ apparent falsity and their use of Russian. On Monday, Ukraine’s State Emergency Service said the national warning system was functioning normally. An NBC News producer in Kyiv encountered no further problems with the app.
Russia’s emergencies ministry said early Monday that a massive cyberattack against its mobile application had spread false information. Screenshots circulated by Russian media and some regional authorities showed a warning claiming that nuclear warheads had been launched toward Russia. Like the Ukrainian messages, its casual wording appeared inconsistent with an official notice.
The Russian ministry later said the public alert system had been restored and was working normally, stressing that the app served only as a supplementary source of information. It attributed the incident to malicious actors without identifying anyone responsible.
The reports followed the end of a temporary ceasefire in the occupied Kherson region of southern Ukraine. Arranged with the involvement of first lady Melania Trump and Pope Leo XIV, the six-day pause passed without violations by either side and enabled hundreds of residents to leave Oleshky, a town that had approached humanitarian catastrophe. It represented the largest de-escalation between Kyiv and Moscow since the war began in early 2022.
In a Sunday post on X, Melania Trump praised both countries for cooperating over Oleshky and expressed hope that the ceasefire could help lead to lasting peace. Ukrainian human rights ombudsman Dmytro Lubinets said he was discussing possible further humanitarian initiatives with his Russian counterpart, Yana Lantratova, and emphasized maintaining their cooperation.
Ukraine’s Armed Forces nevertheless accused Russia on Monday of taking advantage of the pause to rotate troops and strengthen positions in the area. Kremlin spokesman Dmitry Peskov said Ukraine could also have regrouped during the ceasefire, describing such activity as common in those circumstances.
