Russia threatened Tuesday to cut off natural gas and to halt coal deliveries to Ukraine, worsening a dispute over a power blackout in Crimea.
Russian Energy Minister Alexander Novak accused Kyiv of deliberately refusing to help rebuild electricity pylons which were blown up by unidentified, pro-Ukrainian attackers over the weekend, causing the interruption of gas supplies to Russia-annexed Crimea.
The Ukrainian government has denied the accusation as "absolutely groundless." Ukraine also said that it intends to block food shipments to Crimea as reprisal for Moscow's ban on imports of Ukrainian food to Russia.
Novak said that the first phase of an energy bridge from Russia to Crimea would be completed by December 20, two days before the previously set date.
The energy ministry in Moscow said that, in the meantime, Russia was sending 300 mobile generators to the peninsula.
Novak said that Russia may cut natural gas supplies to Ukraine on Tuesday or Wednesday because Kyiv had not made a down payment on future deliveries.
He also said that the Kremlin may halt coal supplies to Ukraine in retaliation for blowing up pylons that caused the interruption of gas supplies from Ukraine, which accounts for most of Crimea's electricity.
Months-long tensions escalating
Power blackouts in Crimea affected almost one million people Tuesday as tension between Kyiv and Moscow on the annexed peninsula has escalated.
The Russian parliament voted overwhelmingly in March 2014 to annex the largely Russian-speaking Crimea, just weeks after pro-Western Ukrainian protests in Kyiv forced Russia-leaning President Viktor Yanukovych from office.
Weeks later, pro-Russian separatists in eastern Ukraine launched a rebellion against Kyiv's rule that triggered a series of trade and travel sanctions against key Russian officials close to President Vladimir Putin. Those sanctions are due to expire in January.
The United Nations has said that over 8,000 people, most of them civilians, have been killed in the conflict.