we know 400 people were inside an art school. no word yet on casualties, but it comes as rescue teams try and pull people out of the rubble at a theatre. hundreds are thought to be trapped there after a theatre housing more than 1,000 was struck. than 1,000 was struck a couple of days ago, and what is making their efforts all the more difficult is fighting breaking out in the streets. there are now russian forces in the heart of mariupol. we understand, suggesting, as feared by the west, that the level of ukrainian resistance might be starting to falter under intense pressure. sustained bombardment, sustained siege for more than two weeks, where more than coming up to 2,500 people are known to have died. the figure is thought to be higher, but nevertheless it has come at a cost for the russians. they have sustained unexpected losses, and the thought from military experts is should mariupol fall, yes, it's strategically significant, it gives the russians a land corridor across the south east