Zürcher Nachrichten - Key moments in the battle for Mariupol

Located on the Sea of Azov, the city, which had a population of 441,000 before the war, is a key prize for Russia in its bid to connect the annexed Crimea peninsula to the west with territory held by pro-Russian rebels in the east.

- Pounded, encircled -

On March 2, a week after the Russian invasion of Ukraine, Moscow's artillery begins pounding Mariupol.

The mayor accuses Russian forces and pro-Russian fighters of seeking to "impose a blockade" by cutting off food supplies and vital infrastructure, including water, electricity and heating.

- Maternity ward bombed -

On March 9, Russia targets a building housing a maternity ward and paediatric hospital in Mariupol, killing three people, including a young girl.

Ukraine and the European Union accuse Russia of a war crime. Russia claims the building is sheltering Ukrainian nationalists and that a heavily pregnant woman photographed being rescued is an actress.

- First evacuations -

Mid-March sees the start of the evacuation of thousands of civilians from the city through a humanitarian corridor.

Earlier evacuation attempts had collapsed with both sides accusing the other of failing to halt fire.

- Theatre destroyed -

On March 16, Russian air strikes raze a theatre sheltering hundreds of people, mostly women and children. It takes days to reach survivors trapped in an underground shelter.

Ukrainian authorities estimate some 300 people were killed.

Moscow denies the attack, blaming Ukraine's far-right Azov battalion, which is based in the city.

- Hellish battle to survive -

On March 21, Kyiv rejects a first Russian ultimatum to Ukrainian forces in the city to surrender.

Civilians who manage to escape in their own vehicles describe apocalyptic scenes of streets riddled with dead bodies and a hellish struggle to survive starvation, thirst and cold amid relentless Russian bombardments.

- 'Last battle' -

On April 4, Mariupol's mayor says the city has been 90 percent destroyed.

A week later, Ukrainian forces say they are preparing for a "last battle" at the sprawling Azovstal steelworks, the last pocket of resistance to Russian control of the city.

Over the following week, Russia issues a string of ultimatums to the troops at Azovstal to give themselves up but they refuse.

Regional authorities say the death toll in the city could exceed 20,000 people.

- Mariupol 'liberated' -

On April 21, Russian President Vladimir Putin declares the "liberation" of Mariupol to be a "success." He orders the Russian military to refrain from storming the Azovstal plant, telling them to besiege it instead, "so that not even a fly can escape".

- Women, children rescued -

On May 7, Ukraine's government announces that all women, children and the elderly sheltering in the plant have been evacuated, amounting to nearly 500 people.

On May 9, pro-Russian forces in Mariupol hold a parade through the ruined streets to commemorate the Soviet victory over Nazi Germany during World War II.

Five days later, a Ukrainian group, Kalush Orchestra, wins the Eurovision song contest and uses the platform to appeal for help for the soldiers holed up inside Azovstal.

On May 17, a first group of more than 260 Ukrainian soldiers surrenders to Russian forces.

They are taken captive by Russian forces, with the wounded admitted to a hospital in a Russian-controlled part of the Donetsk region.

By May 19, 1,730 Ukrainian fighters have surrendered, according to Moscow. Their fate is uncertain. Ukraine wants to swap them for Russian prisoners of war but a pro-Russian separatist leader suggests some will be put on trial.

N.Fischer--NZN