Ukrainian President Volodymyr Zelenskyy said Russian forces not only blocked a humanitarian convoy trying to reach besieged Mariupol with desperately needed supplies on Tuesday but took captive some of the rescue workers and bus drivers. He said the Russians had agreed to the route ahead of time. “We are trying to organize stable humanitarian corridors for Mariupol residents, but almost all of our attempts, unfortunately, are foiled by the Russian occupiers, by shelling, or deliberate terror,” Zelenskyy said in his nighttime video address to the nation.