Russian Emergencies Ministry also says its mobile app suffered a ‘massive cyberattack’, leading to ‘false information’.

Ukraine’s Air Force has said its air raid alert app sent erroneous messages after allegedly being hacked by Russia.

Fake alerts warning of nuclear and chemical threats to areas in and around Kyiv were sent on Sunday, along with warnings of potential street combat. An erroneous message also said Russia’s hypersonic Oreshnik missile had been deployed.

“The air alert app appears to have been subjected to enemy influence,” the Ukrainian Air Force said on Telegram on Sunday. “There is no radiation threat! Stay calm and follow our updates on our channel.”

SPRAVDI, Ukraine’s Centre for Strategic Communications, blamed Russia for the hack in a post on X.

The raid alert app is used across Ukraine to warn people in real time of incoming Russian air attacks. A separate app, specifically for the Ukrainian capital, was working normally, according to Kyiv authorities.

Hours later, early on Monday morning, Russia’s Emergencies Ministry said its mobile app had been hit by a “massive cyberattack”.

The ministry said on Telegram that the attack led to the spread of “false information”.

Russia’s and Ukraine’s announcements follow the end of a truce between the two countries in Kherson.

The localised ceasefire, which began on Tuesday and ended on Sunday, was the longest of the war so far.