ATHENS/BRUSSELS (Reuters) – Greece’s ruling Syriza party dismissed reform demands from the country’s international creditors as “blackmail” on Thursday as crisis talks to avert a debt default and a euro zone exit entered a critical phase. A parliamentary spokesman for Greek Prime Minister Alexis Tsipras’s left-wing party struck a defiant tone a day after euro zone finance ministers accused Athens of refusing to compromise despite a looming deadline to clinch a deal.