By Michelle Nichols and Pavel Polityuk UNITED NATIONS/LVIV, Ukraine (Reuters) – Ukrainian President Volodomyr Zelenskiy told the U.N. Security Council on Tuesday that “accountability must be inevitable” for Russia as he accused invading Russian troops of committing “the most terrible war crimes” since World War Two. The European Union’s executive meanwhile proposed sweeping new sanctions against Russia, including a ban on coal imports, as part of the West’s response to evidence of civilian killings in the northern Ukrainian town of Bucha retaken from Russian forces. Between 150 and 300 bodies …