Ukrainian President Volodymyr Zelensky on Sunday said the Russian military has sustained “unprecedented losses” and that some Russian units have been "80 to 90% destroyed." "Ukrainians have proven they can fight more professionally than an army that has been waging wars for decades in various regions and conditions. We respond with wisdom and courage to the great number of their equipment and soldiers sent to Ukraine," Zelensky said in a video message posted to social media. He then switched from speaking Ukrainian to Russian and said in areas where heavy fighting have taken place, the front line of defense is...