good morning, everyone. i m bianna golodryga. and i m jim sciutto. ukraine says that russia s trying to take revenge for the loss, the sinking of one of the jewels of the russian navy. that ship, the moskvaa, sits at the bottom of the black sea. ukraine s claim of a missile strike on the ship is credible. u.s. officials tell us they have struck back targeting military facilities on the outskirts of the capital kyiv. right now, air raid sirens can be heard across several parts of ukraine as heavy shelling is reported in the donetsk region. and in mariupol, the last two ukrainian military units in that city are working to fend off russian forces. the senior defense officials telling cnn that cnn is in, quote, a dire position. let s begin this morning with cnn s brianna keilar in lviv and western ukraine. brianna, russia claims they have struck a military facility on