U.S. helping Ukraine investigate December power grid hack

A general view shows the facilities of a mobile gas turbine generator, which was turned on due to recent power outages after pylons carrying electricity were blown up, in the settlement of Stroganovka, Simferopol district of Crimea, in this November 22, 2015 file photo. REUTERS/Pavel Rebrov

WASHINGTON (Reuters) - The U.S. Department of Homeland Security said on Tuesday it was helping Ukraine investigate an apparent attack last month on the country's power grid that caused a blackout for 80,000 customers.

Experts have widely described the Dec. 23 incident at western Ukraine's Prykarpattyaoblenergo utility as the first known power outage caused by a cyber attack. Ukraine's SBU state security service has blamed Russia for the incident, while U.S. cyber firm iSight Partners linked it to a Russian hacking group known as "Sandworm."