Any changes to Ukraine's territory would have to be settled in Ukraine by a referendum, according to the country's constitution. "Issues of altering the territory of Ukraine are resolved exclusively by an All-Ukrainian referendum,

Territorial questions are certain to be a key area of focus when Ukrainian President Volodymyr Zelenskiy and European leaders meet U.S. President Donald Trump for talks on Monday to map out a possible peace deal to end Russia's war in Ukraine.

Much of the talk between President Trump and his Ukrainian counterpart, Volodymyr Zelensky, today will center on whether Ukraine is willing to give up land to end the war with Russia. Russian President Vladimir Putin has long sought to control the four Ukrainian regions of Luhansk,