German Chancellor Angela Merkel hit back on Monday at critics in her alliance who have questioned Greece\'s eurozone future by calling for \"solidarity\" with debt-wracked nations. Merkel said in a speech at a folk festival in the southern Bavaria state that Europe needed to be strong with a \"stability union\" not saddled with a \"debt union\", as it battles to resolve the near three-year crisis. But she said constant naysaying about the prospects of stricken countries were unhelpful. \"In such a difficult phase, these countries (such as Greece) have earned our solidarity, in us wanting them to be able to overcome these difficulties,\" Merkel said in the town of Abensberg. Germany, the European Union\'s effective paymaster as its top economy, must push for reforms in countries struggling under the burden of their debt, \"even if they sometimes say we are severe,\" she said. Members of the Bavarian sister party of Merkel\'s Christian Democratic Union have openly spoken of a possible Greek exit from the eurozone or have appeared sceptical over a solution to the debt crisis. Alexander Dobrindt, the secretary general of the Christian Social Union (CSU), a junior coalition partner, told Bild am Sonntag last month that he saw Greece leaving the euro next year. And Markus Soeder, a leading CSU member, has said further aid to Greece would be like \"pouring water on the desert\". Merkel, a vocal advocate for austerity, has softened her tone of late and last week voiced sympathy for Greeks who are hard hit by measures imposed to bring down the country\'s debt and praised Italy for its deficit-cutting efforts.