Russia called on Ukrainian forces in Mariupol to lay down their arms, saying a ‘terrible humanitarian catastrophe’ was unfolding as it said defenders who did so were guaranteed safe passage out of the city and humanitarian corridors would be opened from it at 10am Moscow time (7am GMT) on Monday. Fighting continued inside the besieged city today, regional governor Pavlo Kyrylenko said, without elaborating.  Russia and Ukraine have made agreements throughout the war on humanitarian corridors to evacuate civilians, but have accused each other of frequent violations of those. This comes as today Boris Johnson asked Ukrainian President Volodymyr Zelensky what his military requires in Ukraine’s battle against Russia’s invasion…