KYIV, Ukraine (AP) Ukraine braced for a climactic battle for control of the besieged countrys industrial east after Russian forces withdrew from the shattered outskirts of Kyiv to regroup and intensify their offensive across the Donbas region, where authorities urged people to evacuate before time runs out.

The mayor of the southern port city of Mariupol said Wednesday that more than 5,000 civilians had been killed there. Meanwhile, in areas north of the capital, Ukrainian officials gathered evidence of Russian atrocities amid signs Moscows troops killed people indiscriminately before retreating over the past several days.

In his nightly address, Ukrainian President Volodymyr Zelenskyy warned that the Russian military is building up its forces for a new offensive in the east, where the Kremlin has said its goal is to liberate the Donbas, Ukraines mostly Russian-speaking industrial heartland. Ukraine, too, was preparing for battle, he said.

We will fight and we will not retreat, he said. We will seek all possible options to defend ourselves until Russia begins to seriously seek peace. This is our land. This is our future. And we wont give them up.