Afghanistan, Nov. 2 -- Fake warnings of nuclear danger, radiation threats and street fighting were sent to mobile emergency alert applications in Ukraine and Russia, prompting authorities to investigate suspected cyberattacks and reassure the public.

NBC News reported Monday, November 2, that Ukraine's emergency alert application was compromised late Sunday, with Russia's emergencies ministry reporting a separate cyberattack on its own mobile alert system hours later. It remains unclear whether the two incidents were connected or who was responsible.

In Ukraine, users began receiving alarming messages at around 10:45 p.m. local time. The alerts warned people to stay indoors because of alleged radiation and chemical threats and street clas...