Prime Minister Alexis Tsipras raised the stakes in Greece’s showdown with creditors, rejecting demands for more austerity to receive bailout funds and opting for an unconventional deferral of International Monetary Fund payments. Tsipras told German Chancellor Angela Merkel and French President Francois Hollande during a midnight call Thursday that a list of demands needed to unlock bailout funds hammered out earlier this week by officials from the IMF and the euro area can’t be a basis for a deal, said a Greek official, who asked not to be identified discussing private talks.