"Russia understood that Ukraine has a powerful energy system, and therefore ... attacked distribution substations, which connected (different) regions," Podolyak said. He also ruled out retaliatory strikes on Russian energy infrastructure. Power has been restored to more than 4,000 towns and villages since the strikes, Shmyhal said, but warned of difficult times ahead. "We are planning to make more candles and order more materials because of these blackouts," she said. Register now for FREE unlimited access to Reuters.com RegisterReporting by Stefaniia Bern, Max Hunder, Jonathan Landay; writing by Matthias Williams.

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