US President Joe Biden is expected to announce more sanctions against Moscow at the NATO summit on Thursday, March 24, as, four weeks into the Ukraine war, Russia doubles down on its bombardment of Ukraine’s cities. In the past 48 hours, some 250 bombers are day by day taking part in the relentless blitz, compared with the previous 60. They are now focusing on Kiev, Chernihiv and Kharkiv, where fierce resistance has contained the Russian forces’ advance. None has fallen – any more that the southern port of Mariupol, where a whole city is being ground down to rubble. The UN says as many as 10 million people have fled their homes – either across the border or to other parts of Ukraine.