The emergency meeting of eurozone finance ministers promises to be bruising, with Greek demands for a cash lifeline and a relaxation of austerity facing resistance from Germany in particular.
Markets worldwide are spooked by the renewed threat of Greece crashing out of the euro, with the country's massive EU-IMF bailout set to expire at the end of February, leaving it at the risk of a default.
Greek bond yields jumped and the Athens stock market plummeted more than 4.5 per cent hours before the talks as the two sides seemed far apart.
The new government is riding a wave of popularity in Greece, emboldened by the 40-year-old premier's defiance of Germany and austerity, which Tsipras has tempered with pledges to keep Greece in the eurozone.
But Greece has also ramped up threats to look to Russia or China for help, further raising the stakes for European unity as it wrestles with economic stagnation and the crisis in Ukraine.
Defence Minister Panos Kammenos on Tuesday said Athens could look for a "plan B" if the EU fails to help, which could involve Washington, Beijing or Moscow.
