German business leaders urged Chancellor Angela Merkel to take a tough line with Greece at an emergency summit of euro zone leaders later on Monday, saying only reform concessions from Athens could keep the country in the euro zone. "Greece must deliver today," Ingo Kramer, head of Germany's BDA employers association, told German newspaper Bild. Ulrich Grillo, president of Germany's BDI industry association, suggested in Bild that the euro zone was not obliged to keep Greece in the bloc.