According to Aljazeera, civilians have a hard time evacuating from Mariupol which was surrounded by the Russian troops:
Previous attempts to establish evacuation corridors to allow civilians to escape the city, and to allow humanitarian aid to enter, have fallen apart as earlier ceasefires collapsed.
The two parties have traded the blame for such failures, with Ukrainian authorities accusing Russia of deliberately opening fire on aid convoys heading towards Mariupol. Russia has blamed Kyiv for sabotaging ceasefire agreements and holding civilians hostages.
I do not understand why the Russian troops would not allow the civilians to evacuate. Isn't trying to conquer a city easier if virtually only the combatants remain? It would also diminish the likelihood of committing war crimes committed during the bombardments.
It would make even less sense for the Ukrainians to sabotage the ceasefire, that's why my question is focused on the Russian part of the possible ceasefires agreement.