In Kyiv, the city's state administration said trains were halted, and escalators stopped working due to low voltage in the external power grid feeding the subway system.
"The metro has been suspended due to low voltage in the network. Underground metro stations can currently operate as shelters (on backup power supply)," Mayor Vitaliy Klitschko wrote on Telegram.
Kharkiv Metro announced that train movement on all lines was temporarily suspended for technical reasons and said further updates on restoration would be provided separately.
Ukraine’s largest private energy company, DTEK, reported emergency power cuts in Kyiv city and the surrounding region. Social media users reported emergency blackouts in multiple other parts of the country as well.