In the eastern Donbas region, Russia and Ukraine are locked in the bloodiest infantry battle in Europe since World War Two, after Moscow launched a winter offensive with hundreds of thousands of freshly called up reservists and mercenaries. They are lobbing mortar bombs at us," Oleksandr told Reuters, describing Russian units advancing in three-man fire teams, with another wave behind them sent to replace them when they are killed. Russia said it had agreed to let it be extended for 60 days, in what the Kremlin called a gesture of "goodwill," but would block any further extension unless it received more guarantees from the West for exports of its own fertilizer and crops