Fake nuclear warnings issued after Ukrainian and Russian air alert apps hacked

In Russia, the government said its app had also been targeted by "a massive cyberattack", which sent "fake information to the public".

It warned some users that "nuclear warheads mounted on P1-Suns [a Ukrainian attack drone] had been launched at all regions of Russia".

The alert, which included profanities, opened with a message telling residents there was a "risk of [things] getting lively" and told them to "stock up urgently on food for three weeks and hide".

On Monday morning there was no sense the messages had caused widespread panic in Russia and the incident was not being prominently featured on media outlets.