The bombardment took place as Ukrainian President Volodymyr Zelensky is heading to the Munich Security Conference, where he is expected to meet with top U.S. officials.

Ukraine called on its allies on Wednesday to help it import more natural gas as it moved to increase gas imports by a third to 22.6 million cubic meters following a series of Russian missile attacks on Ukrainian gas facilities.

Ukrainian natural gas production facilities were damaged in a Russian attack on Ukraine's central Poltava region overnight, the state-run oil and gas firm Naftogaz and Energy Minister German Galushchenko said on Tuesday.