BELBEK, Crimea — In the early morning hours of March 4, a group of unarmed Ukrainian soldiers marched from their barracks on the territory off Belbek military airfield near Sevastopol to demand that the heavily armed Russian troops who have besieged their base allow them to carry out their work.

The group, comprised of about 100 men, carrying a Ukrainian flag and the red flag of their unit, walked onto the airfield about a half-kilometer away from the runway and directly toward four Russian military vehicles and several officers, some of whom fired warning shots in the air in an attempt to stop the Ukrainians from advancing.