A Russian lawmaker calls President Biden's decision to let Ukraine fire U.S. missiles deep into Russia a "very big step toward the beginning" of a third world war.

Russia on Sunday launched a massive drone and missile attack on Ukraine, described by officials as the largest over the past months, targeting energy infrastructure and killing civilians. The attack came as fears are mounting about Moscow’s intentions to devastate Ukraine's power generation capacity ahead of the cold winter.

President Volodymyr Zelensky on Sunday said "missiles will speak for themselves," following reports that U.S. President Joe Biden has authorized Ukraine to conduct strikes deeper into Russian territory.