LVIV, Ukraine (AP) — The humanitarian crisis in Ukraine is deepening as Russian forces intensify their shelling and food, water, heat and medicine grow increasingly scarce. Ukraine says it is facing a medieval-style siege by Moscow to batter it into submission. A third round of talks between the two sides Monday ended with a top Ukrainian official saying there had been minor, unspecified progress toward establishing safe corridors that would allow civilians to escape the fighting. Russia’s top negotiator says he expects those corridors to finally start functioning Tuesday.