RAMSTEIN AIR BASE, Germany — Ukraine needs the ability to strike deep within Russia now, President Volodymyr Zelenskyy urged top U.S. and allied military leaders Friday in Germany, as Kyiv continues to press its case that without long-range strikes and bolstered air defenses, it faces a bleak winter. The meeting of the Ukraine Defense Contact Group was taking place during a dynamic moment in Ukraine’s fight against Russia, as it conducts its first offensive operations of the war while facing a significant threat from Russian forces near a key hub in the Donbas.