Ukrainian authorities say Russia’s military bombed an art school sheltering about 400 people in the besieged port city of Mariupol. Refugees arriving in western Ukraine from the port city say “battles took place over every street” weeks into a crippling Russian siege. Western military analysts say that even if the city is taken, the troops battling for control there may be too depleted to secure Russian breakthroughs on other fronts. Three weeks into the invasion, many see the conflict shifting to a war of attrition, with bogged down Russian forces launching long-range rockets as Ukrainian forces carry out hit-and-run attacks. Analysts warn a stalemate could be even deadlier.