Reports show an encounter in the city of Mariupol, the tenth-largest city in Ukraine, the second-largest in Donetsk Oblast, and home to the largest trading port in the Azov Sea. Exports of grain, iron and steel, and heavy machinery pass through the port. Military operations have been observed in the Donbas Region, Kyiv, and Chernihiv. United Nations figures show that more than four million Ukrainians have fled their homeland.