Tsipras will face his 18 eurozone counterparts in Brussels as the country's economy gasps for air, with banks closed until at least Thursday amid fears the Greek banking system is imploding.
German Chancellor Angela Merkel and French President Francois Hollande, heads of eurozone's largest economies, presented a united front on the eve of the summit, urging Tsipras to make "precise" proposals in a bid to rebuild shattered trust and restart negotiations.
The meeting of the eurozone's two most powerful leaders came a day after Greeks rejected reform terms for a new EU-IMF bailout in a historic referendum that was a political victory for Tsipras but infuriated Europe.
For her part, Merkel said the conditions for a new Greek rescue package "have not yet been met."
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Merkel is under immense pressure at home to stay firm in talks with Greece.
But France's number two leader Prime Minister Manual Valls made clear that a Greek euro exit was not an option, drawing the line much more firmly than austerity-minded Berlin has so far.
"France is convinced that we can't take the risk of Greece leaving the eurozone," Valls told French radio today, adding that France would do "everything" to keep it in.
European Commission head Jean-Claude Juncker also said 'Grexit' must be avoided but warned against expecting a deal today.
The emergency eurozone summit is set to begin at 2130 IST, after a meeting of eurozone finance ministers at which Greece's new finance minister Euclid Tsakalotos will make his first appearance.