Ukrainians boarded buses to flee the besieged eastern city of Sumy on Tuesday, the first evacuation from a Ukrainian city through a humanitarian corridor agreed with Russia.
Ukraine said a separate convoy of 30 buses was also headed to Mariupol to evacuate residents from that southern port, which has been encircled without food, water, power or heat and subjected to relentless bombardment for a week.
The United Nations said the number of refugees who have fled Ukraine had surged past 2 million, describing the flight as one of the fastest exoduses in modern times.