The mass evacuation of Mariupol was underway Monday with Ukrainian authorities hoping thousands more residents will escape the devastated city that once was home to almost 500,000 people.

Mayoral adviser Petro Andryushchenko told Radio Svoboda that buses were rolling toward Zaporizhzhia, about 140 miles west of Mariupol. People were also encouraged to join the exodus in their own cars.

The Ukraine military said civilians were already arriving in Zaporizhzhia, a city of about 750,000 people, and were being provided hot meals, physical and psychological examinations and medicines.

“All evacuees will receive a calm refuge,” the statement said. “Finally, these people will be able to feel safe.”

According to some estimates, about 100,000 people were trapped in Mariupol, with little access to food, water and utilities. Several hundred of them remained at a sprawling steel plant that is the last major holdout in the Russian-occupied city – along with nearly 500 wounded soldiers and an unknown number of dead bodies.

More than 100 women, children and the elderly were evacuated from the Azovstal plant Sunday before Russian shelling forced a temporary halt to the evacuation effort. The Russian military said 69 chose to be evacuated to Ukraine-controlled territories, while 57 others asked to stay in the areas under Russian control.

President Volodymyr Zelenskyy told Greek state television that civilians remaining in the plant were afraid to board buses because they believed they would be taken to Russia. He said he had U.N. assurances they would go to Ukraine-controlled areas.

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Latest developments:

►A Russian missile strike caused deaths and injuries on Monday in Odesa, the governor of the southwestern region, Maksym Marchenko, said on social media. He didn’t specify how many were killed or injured. Ukrainian authorities previously said Russian forces destroyed a strategic bridge in Odesa, cutting access to shipments of weapons and other cargo from neighboring Romania.