Kyiv's troops are struggling to hold territory in Russia's Kursk region and may be forced to retreat, reports say.

World War I involved 32 nations from 1914 to 1919. It redrew the world map and reshaped many borders in Europe. The collapse of the Russian Empire created Poland, the Baltics, and Finland.

as a map shows the latest state of play. It comes amid recent advances by Ukrainian forces near Toretsk and Pokrovsk and concerns about continued United States aid for Kyiv's war effort.