(Reuters) -The European Union is dealing with an increase in legal and illegal arrivals by migrants, prompting some member states to temporarily re-introduce border controls within what is normally a zone of free movement. The bloc’s Schengen rules allow such action “as a last resort” in cases that are deemed serious threats to internal security or public policy. These countries have reinstated stricter checks: * Austria introduced checks at its border with the Czech Republic in October, set to last until Feb. 16, 2024. As of November, it extended border controls with Slovenia and Hungary unti…