Ukraine said its official air-raid alert application was apparently hacked on Sunday, sending false warnings of radiation and chemical threats in Kyiv; authorities said there was no danger.
The alerts told residents not to go outside, Fox News reported. Ukraine blamed Russia for the false messages, according to Al Jazeera. The BBC said authorities urged people to remain calm and use official information channels.
Russia's Emergencies Ministry also reported what it called a massive cyberattack on its mobile application, which it said caused false information to appear, Al Jazeera reported. Deutsche Welle reported that both countries said applications used for public emergency alerts had been targeted.