reporter: a grueling bloody battle as russian forces try to extinguish the last pocket of ukrainian fighters holed up in maricopa s sprawling steel plant. video from russian straightists show tanks moving in, a barrage of explosions from the air. according to a senior defense official, a couple thousand u.s. forces are still in the devastated city. russia s defense minister claims putin s forces have reliably blocked the ukrainian fighter, cornered in the plant. the ukrainian foreign minister says the plant still holds, despite the relentless russian attacks. outfront spoke to one of the ukrainian commanders inside the plant on monday. at the time he spoke about their fight. translator: we will be fighting as long as it is needed, despite extremely difficult conditions. reporter: according to the mayor of mariupol, there are still hundreds of civilians inside that plant, including 30