In a major change of U.S. policy, President Biden has given Ukraine the green light to begin striking inside Russia with U.S.-supplied long-range missiles. The decision comes just two months before Donald Trump takes office and as North Korean troops have begun supporting Russia on the battlefield.

The New York Times reports Biden’s own aides were divided on the decision, with some fearing this could lead to Russia retaliating against the U.S. Earlier today, the Kremlin accused the Biden administration of adding “oil to the fire.” Ukrainian President Volodymyr Zelensky spoke on Sunday.

President Volodymyr Zelensky: “Today there’s lots of talk in the media about us receiving permission for respective actions. But strikes are not carried out with words. Such things are not announced. Missiles will speak for themselves. They certainly will. Glory to Ukraine.”

Over the weekend, Russia launched a massive missile and drone attack on Ukraine’s power grid, resulting in major blackouts. In the city of Sumy, a Russian missile hit a residential building, killing 11 people, including two children.