KYIV, Ukraine (AP) — Mariupol appeared on the verge of falling to the Russians on Tuesday as Ukraine moved to abandon the steel plant where hundreds of its fighters had held out for months under relentless bombardment in the last bastion of resistance in the devastated city.

The capture of Mariupol would make it the biggest city to be taken by Moscow's forces in the war yet and would give the Kremlin a badly needed victory, though the landscape has largely been reduced to rubble.

More than 260 Ukrainian fighters — some of them seriously wounded and taken out on stretchers — left the ruins of t...