ukraine. where fighting is intensifying. president zelenskyy said no matter how many russia soldiers are brought here we will fight, we will defend ourselves and not give up anything that is not ukrainian. norah? o donnell: chris livesay in ukraine, thank you. and stay safe. tonight there is growing concern about russian threats here at home. u.s. authorities warn that the kremlin could launch cyberattacks on american soivment experts say this could im ethpublicto banks to the eney sector. 60 minutes, cbs s bill chit ker spoke with dmitri alperovitch of crowdstrike and a member of the homeland security advisory council. so all of these things they can do. what is the one that troubles you the most. an attack on the oil & gas industry where they go after the safety systems again. and it can cause cascading effects and fires and potentially explosions and people die.