MADRID (Reuters) – The different inflation levels in euro zone countries make the European Central Bank’s monetary policy action challenging, Spanish Economy Minister Nadia Calvino said on Friday. “We see a (inflation) downward trend in our country which contrasts with the upward trend in a large part of the European Union,” she told reporters. “There are different macroeconomic and inflation situations in the different countries and that is a challenge for the ECB when articulating a unique monetary policy.” (Reporting by Inti Landauro)