Russia-Ukraine war: Key things to know about the conflict

Russia has escalated its attacks in western Ukraine, hitting a military base near the border with Poland. Ukrainian President Volodymyr Zelenskyy said 35 people were killed in that attack at the base, and he called Sunday a “black day.” Zelenskyy again called for NATO leaders to establish a no-fly zone over Ukraine. Also Sunday, U.S. video journalist Brent Renaud was killed and another U.S. journalist was injured when they were attacked by Russian forces near Kyiv. Meanwhile, the International Committee of the Red Cross said hundreds of thousands of residents in Mariupol are facing shortages of food, water and medicine. A humanitarian convoy to bring aid to Mariupol was blocked Sunday, but it will try to reach the city Monday.