Ukraine is pushing for permission from its Western partners to use the long-range missiles they have provided to strike targets deep inside Russia, as Ukrainian forces struggle to hold back Russian advances in eastern Ukraine. Russia has warned that it would consider allowing such long-range strikes an act of war, and Ukraine's Western allies are wary of antagonizing the country with the world's largest nuclear arsenal. The issue is likely to weigh heavily on White House meetings Friday between President Joe Biden and British Prime Minister Keir Starmer, as well as with Ukrainian President Volodymyr Zelenskyy later this month.