The head of NATO’s military committee says that Ukraine has the solid legal and military right to strike deep inside Russia to gain combat advantage, reflecting the beliefs of a number of U.S. allies.

As the war escalates, Ukrainian President Volodymyr Zelenskyy has been asking allies to allow the use of Western missiles to strike targets inside Russia.

The Russian president said Western support for Ukrainian strikes deep inside Russia would put his country and NATO “at war.”