Mariupol

Mariupol is a strategic port city on the northern shore of the Sea of Azov in the Donetsk region of Ukraine. Before the 2022 invasion it had a population of approximately 430,000 and hosted Ukraine's largest steel industry complex, including the Azovstal plant. Russia captured Mariupol on 20 May 2022 following a three-month siege and the last stand of Ukrainian forces inside Azovstal, making it Russia's largest territorial gain in the early phase of the war. Russia has since administered Mariupol as part of the illegally annexed Donetsk Oblast.

Mariupol's fall and the fate of its Azovstal defenders became among the most internationally documented events of the war. Many of the soldiers captured at Azovstal were held in Russian captivity for approximately four years before appearing in the May 2026 prisoner exchange, in which the first 205-for-205 tranche was executed on 15-16 May 2026. Ukraine's stated position is that Mariupol's return is a condition of any peace settlement it could present to its population.

Under Russian occupation, Mariupol has undergone reported forced demographic change and infrastructure reconstruction intended to integrate it into Russia. Western and Ukrainian monitoring groups document the removal of Ukrainian cultural markers and the settlement of Russian citizens. The city's legal status — whether Ukrainian territory under temporary occupation or formally annexed Russian territory — is central to why the Istanbul talks failed to advance: Russia's demand that Ukraine recognise its sovereignty over Mariupol and three other annexed regions was rejected outright.