EXPLAINER: Who were Mariupol’s last defenders?


              FILE - Volunteers with the right-wing paramilitary Azov National Corps stand to attention less than a month before the country's presidential vole during a march along the main street in Kiev, Ukraine, on March 2, 2019. The Ukrainian forces who made a determined last stand in a Mariupol steel mill against Russian troops were a mixture of seasoned soldiers, border guards, a controversial national guard regiment and volunteers who took up arms in the weeks before Russia's invasion. (AP Photo/Efrem Lukatsky, File)
            
              FILE - In this photo provided by Azov Special Forces Regiment of the Ukrainian National Guard Press Office, an Azov Special Forces Regiment's serviceman, injured during fighting against Russian forces, poses for a photographer inside the Azovstal steel plant in Mariupol, Ukraine, on May 10, 2022. The Ukrainian forces who made a determined last stand in a Mariupol steel mill against Russian troops were a mixture of seasoned soldiers, border guards, a controversial national guard regiment and volunteers who took up arms in the weeks before Russia's invasion. (Dmytro 'Orest' Kozatskyi/Azov Special Forces Regiment of the Ukrainian National Guard Press Office via AP)
            
              FILE - A young woman holds a weapon during a basic combat training for civilians, organized by the Special Forces Unit Azov, of Ukraine's National Guard, in Mariupol, Donetsk region, eastern Ukraine, on Feb. 13, 2022. The Ukrainian forces who made a determined last stand in a Mariupol steel mill against Russian troops were a mixture of seasoned soldiers, border guards, a controversial national guard regiment and volunteers who took up arms in the weeks before Russia's invasion.  (AP Photo/Vadim Ghirda, File)
            
              FILE - In this photo provided by Azov Special Forces Regiment of the Ukrainian National Guard Press Office, an Azov Special Forces Regiment's serviceman, injured during fighting against Russian forces, poses for a photographer inside the Azovstal steel plant in Mariupol, Ukraine, Tuesday, May 10, 2022. The Ukrainian forces who made a determined last stand in a Mariupol steel mill against Russian troops were a mixture of seasoned soldiers, border guards, a controversial national guard regiment and volunteers who took up arms in the weeks before Russia's invasion (Dmytro 'Orest' Kozatskyi/Azov Special Forces Regiment of the Ukrainian National Guard Press Office via AP)
            
              Ukrainian servicemen sit in a bus after leaving Mariupol's besieged Azovstal steel plant, near a penal colony, in Olyonivka, in territory under the government of the Donetsk People's Republic, eastern Ukraine, Friday, May 20, 2022. (AP Photo)
            
              FILE - Smoke rises from the Metallurgical Combine Azovstal in Mariupol during shelling, in Mariupol, in territory under the government of the Donetsk People's Republic, eastern Ukraine, Saturday, May 7, 2022. Russia claimed to have captured Mariupol on Friday in what would be its biggest victory yet in its war with Ukraine, after a nearly three-month siege that reduced much of the strategic port city to a smoking ruin. (AP Photo/Alexei Alexandrov, File)
            
              Ukrainian servicemen sit in a bus after they left the besieged Mariupol's Azovstal steel plant, near a penal colony in Olyonivka, in territory under the government of the Donetsk People's Republic, eastern Ukraine, Friday, May 20, 2022. (AP Photo)
            
              Ukrainian servicemen sit in a bus after leaving Mariupol's besieged Azovstal steel plant, near a penal colony, in Olyonivka, in territory under the government of the Donetsk People's Republic, eastern Ukraine, Friday, May 20, 2022. (AP Photo)
            FILE - In this photo taken from video released by the Russian Defense Ministry Press Service on Wednesday, May 18, 2022, Ukrainian servicemen leave the besieged Azovstal steel plant in Mariupol, Ukraine. Breaking its silence on prisoners of war, the Red Cross said Thursday, May 19, 2022 it has registered "hundreds" of Ukrainian prisoners of war who left the giant Azovstal steel plant in Mariupol after holding out in a weeks-long standoff with besieging Russian forces. (Russian Defense Ministry Press Service via AP, File)