By Alan Charlish MEDYKA, Poland (Reuters) – Ukrainians fleeing into central European pleaded for Western nations to take tougher steps against Russia following Moscow’s invasion that has created more than 1 million refugees. At the Medyka crossing, Poland’s busiest, along its roughly 500-kilometre (310-mile) border with Ukraine, refugees called for a no-fly zone over Ukraine — something NATO powers have so far ruled out on the grounds it would risk escalating the conflict beyond Ukraine. “Please close the sky,” said Solomiya Zdryko, 18, who fled from Lviv in western Ukraine. “I know that it’s…