By GEIR MOULSONBERLIN (AP) â¿¿ Greece's prime minister stressed his country was determined to win back credibility in Europe, and was delivering on the reforms and austerity needed to achieve that goal, as he met Tuesday with German Chancellor Angela Merkel. Antonis Samaras' visit to Berlin was his second since taking office last summer. "I would like to make clear up front that our country is undertaking great efforts that are linked with great sacrifices to get things back on track," Samaras said during a brief appearance alongside Merkel before they met at the chancellery. "We are trying to win back credibility, on the part of the people of Europe and on the part of the markets." Greece has been kept afloat since May 2010 by rescue loans from the other 16 European Union countries that use the euro and the International Monetary Fund. In return for the loans, the lenders â¿¿ Merkel's Germany in particular â¿¿ have insisted on a series of economic reforms, tax raises and spending cuts. Merkel said she would "of course be interested in what progress the implementation of the Greek reform program is making," but didn't offer any assessment. The two leaders took no questions. The German government said after the talks that they discussed progress on tax reforms and other plans, and that Samaras set out Greece's efforts to combat tax evasion. They also discussed possibilities for further German-Greek cooperation, the government said without elaborating. In remarks to reporters earlier Tuesday before he attended a closed-doors conference, Samaras said he considers "the glass half full" and was in Berlin with a message of optimism. "We are delivering and Europe is helping," he said. Ahead of the meeting, Merkel stressed the need for greater economic integration across Europe. EU nations are, among other things, setting up a banking union to better oversee their financial sector, but have yet to agree on key details.