Ukraine's air-raid alert app began flashing false warnings of a nuclear strike, chemical attack and street-to-street combat in and around Kyiv late Sunday, officials said, just hours before Russia's own emergency-alert app reported a nearly identical breach.

The Ukrainian Air Force said the official air-alert application "appears to have been subjected to enemy influence" after users across the capital received a string of bogus push notifications, including one claiming Russia had launched its nuclear-capable Oreshnik hypersonic missile. The Air Force moved quickly to calm the panic, writing on Telegram: "There is no radiation threat! Stay calm and follow our updates on our channel." Ukraine's Centre for Strategic Communications, known as SPRAVDI, publicly blamed Russia for the intrusion, though Moscow has not been independently confirmed as the source.

A mirrored attack in Moscow

Hours later, in an almost mirror-image incident, Russia's Ministry for Emergency Situations said its own mobile warning app — used to alert citizens to incoming drone attacks — had suffered what it called a "massive cyberattack, allowing attackers to send fake information to the public," according to a Telegram statement cited by CNBC. The ministry did not say who it believed was responsible.

"THE AIR ALERT APP APPEARS TO HAVE BEEN SUBJECTED TO ENEMY INFLUENCE. THERE IS NO RADIATION THREAT."

CNN reports that few people appear to have been fooled by either round of fake alerts, and that Ukrainian officials disabled push notifications on the compromised app while confirming that backup warning systems, including physical sirens, continued working normally. A separate app used specifically in Kyiv was unaffected and continued operating correctly throughout the incident, city authorities said.

The dueling hacks landed at a tense moment in the war. A rare, six-day localized truce in the Russian-occupied part of the Kherson region — the longest pause in fighting of the war so far — had just expired on Sunday, raising fears of renewed fighting in the area. The ceasefire had allowed some evacuations from the occupied town of Oleshky.

Officials in both countries say the apps are being restored. Ukraine's air-alert system has been a critical piece of civilian infrastructure since Russia's 2022 invasion, delivering real-time warnings of incoming missile and drone strikes to tens of millions of phones. Any disruption to its credibility — even a brief one — carries real risk in a country where seconds of warning can mean the difference between reaching a shelter and not.

Neither government has announced an official attribution or response. Kyiv's cybersecurity agencies and Western partners have in recent weeks pledged additional support for Ukraine's digital infrastructure, as both sides increasingly use cyber operations alongside conventional strikes.