War in Ukraine live updates: A defiant Ukraine rejects Russia's demand to surrender Mariupol

Russia offered the ultimatum Sunday: Surrender Mariupol — where a city official says thousands of civilians in bomb shelters are running out of food — by early today, and Russian troops would let civilians leave and humanitarian aid enter. Ukrainian officials refused. In the capital, Kyiv, Russian strikes destroyed a shopping center, killing more civilians.
Here's what else we're following today:
A shift change at Chernobyl: Russian troops have allowed about half of the staff at the damaged plant to leave for the first time since they took control of the site nearly four weeks ago.
The last European Union diplomat in Mariupol leaves: Greek Consul General Manolis Androulakis had stayed in the besieged city to help ethnic Greek families evacuate.