Fake alerts warn of nuclear danger as Ukraine and Russia report emergency app hacks - NBC News

Authorities said the country’s emergency alert application had been targeted in a cyberattack, and hours later Russia said its own alert system had also been hacked. The dueling accusations came just as a rare humanitarian ceasefire between the two sides ended, raising fears of intensified fighting rather than a move toward broader peace.

Residents in Ukraine have become used to the unsettling alerts that buzz their phones with news of incoming Russian missiles and drones — a service millions rely on to seek shelter before the attacks hit their cities. But the warnings Sunday night immediately stood out.

The messages, which began around 10:45 p.m. Kyiv time (3:45 p.m. ET), warned residents not to go outside because of radiation hazard, chemical threat and street fights.

Another message professed, in Russian, that all of Ukraine was under nuclear alert. “Don’t worry,” it added. “Oreshnik is in action,” referring to Russia’s nuclear-capable hypersonic missile.

That message referenced a Telegram channel called Hitcorecorp. Major pro-Kremlin Telegram channel Mash said it spoke with the group and that it took responsibility for the hack. NBC News could not verify who the group is and whether it was responsible for the alerts.

Shortly after the alerts went out late Sunday, Ukraine’s air force said the country’s Air Alert app had most likely been “compromised by the enemy,” confirming there was no “radiation threat” and urging calm.

In separate statements, the app’s creators said “unauthorized third parties interfered with the operation of the app,” forcing them to temporarily suspend its operations. They later called the incident a “cyberattack,” saying it was gradually restoring the service. “The team is carrying out additional measures to protect the app in order to prevent similar situations in the future,” one of the statements said.

Ukrainian media reported that users across the country received the alert, and authorities in the western Lviv region reported that some of the public warning sirens and loudspeaker systems broadcast a “radiation hazard” signal.

“I was outside with my dog when the first alert came,” said Olena Yermakova, 32, a researcher in Kyiv.

She picked up her dog and ran inside, she said, before checking the news to see what was happening.

Because the message was in Russian, “I thought it was a hack by the Russians,” she said. “But the seconds before that were absolutely terrifying. I started running through a checklist in my head of what to do during a nuclear threat and whether I had all the supplies at home, and my hands started shaking.”

Still, many other Ukrainians did not appear unduly alarmed or panicked by the alerts. In fact, many shared memes online, poking fun at what they saw as a blatant fake and the fact the warning was issued in Russian. “No one was particularly surprised,” a user wrote on X. “They might as well have thrown in a dinosaur attack, too.”

The State Emergency Service of Ukraine said Monday the national alert system was operating normally, and an NBC News producer in Kyiv did not experience any further issues with the Air Alert app.

Meanwhile, Russia’s emergencies ministry also said early Monday that its mobile application suffered a “massive cyberattack,” resulting in what it said was “dissemination of fake information to the public.” The public alert system was restored and was operating normally, it said shortly after. It emphasized that the app was only “an additional, supplementary information service.”

Screenshots shared by Russian media and some regional authorities suggested the alert, issued in Russian, warned of “nuclear warheads” launched at Russia. As with the Ukrainian alert, the wording was casual and did not appear official.

Russian authorities did not say who was to blame for the alleged cyberattack, only saying “malicious actors” were behind it.

It was not immediately clear whether the two incidents were linked.

It came just hours after a temporary ceasefire between Kyiv and Moscow came to an end in the occupied southern Ukrainian region of Kherson.

The truce, brokered with involvement from first lady Melania Trump and Pope Leo XIV, held without violations from either side for six days, allowing the evacuation of hundreds of residents from the front-line town of Oleshky, which had been on the brink of a humanitarian catastrophe.