Mariupol cries for help
I know some are concerned about the despised Azov battalion fighting in Mariupol, but you need to understand, they are not the only people there. Ukraine has many troops from other parts of their military in the city. And then there are the civilians. I have recently seen a figure of about 350,000 civilians left in this city. And they are not all Ukrainian. The city was about evenly split, with a slight edge to Ukrainians, between Russians and Ukrainians. You can bet that Putin cares not if the civilians killed are Ukrainian or Russian. Then there are the minority groups the largest of which is a Greek minority that dates to ancient times.
Mariupol needs to be relieved with some sort of corridor. Diplomacy will not work with the Russians. They respect no agreements or truces. It must be a military effort to relieve the city. Just from the information I have witnessed, time is of the essence.
On Edit: The Russians must not be allowed a land bridge to Crimea. They would have to defeat Mariupol for such a land bridge. This would cut Ukraine off from the sea, even if Odessa holds. The Russians, if Mariupol falls, will never allow a Ukrainian navy to be established or Ukrainian cargo shipping, they will essentially have control of the southern Ukrainian coastline.