Russia and Ukraine say their emergency warning apps have been hit by apparent cyber-attacks, causing alarming false warnings to be sent, the BBC reports. Moscow says a “massive cyber-attack” has affected its app but insists its wider alert system is “operating as normal”. A Ukrainian espionage group claims the messages included fake warnings of nuclear strikes inside Russia. This comes shortly after Ukraine’s air raid warning app sent out false warnings of a radiation threat in Kyiv, following an apparent hack. Ukraine has blamed Russia for the hack on its app, while Moscow is yet to say who it believes is behind the cyber-attack on its system.