Ukraine has announced it will probe an alleged cyberattack on its power grid believed to have been carried out by Russia.
Prykarpattyaoblenergo, a power provider based in western Ukraine, blame failures in its grid on Dec. 23 on "interference."
Ukrainian secret service SBU pointed the finger at "Russian security services," accusing them of launching a malware attack on the system.
"It was an attempt to interfere in the system, but it was discovered and prevented," an SBU spokeswoman told Reuters on Thursday.
Russia has neither denied nor accepted the accusation.
Relations between Russia and Ukraine soured after Russia annexed the breakaway Crimean Peninsula in March 2014, just weeks after Ukraine’s former pro-Russian president Viktor Yanukovych fled pro-EU protests in Kiev.
Fierce fighting has also been taking place in Ukraine’s east between government forces and Russian-backed separatist rebels.