The President of the European Council says that Sunday is the final deadline for resolving the Greek debt crisis.
Donald Tusk was speaking after a crisis meeting of Eurozone leaders in Brussels tonight.
He said the Greek government has to set out detailed proposals to its creditors by Thursday.
That will be followed on Sunday by a meeting of all European Union leaders to try and finalise a deal.
Donald Tusk says time has almost run out:
All 28 member states will attend the "decisive" summit on the Greek debt turmoil on Sunday, Italian Prime Minister Matteo Renzi confirmed.
"I hope and believe a definitive solution for Greece will be possible on Sunday," Mr Renzi told reporters.
German Chancellor Angela Merkel said Greece needed a debt programme that would last for "several years".
Taoiseach Enda Kenny says everyone should work towards keeping Greece in the euro:
The Greek government has confirmed it will present a revised bailout request tomorrow "taking into account" the concerns of its international creditors.
The confirmation came as a crisis summit of Eurozone heads of government including the Taoiseach got underway in Brussels.
The modified proposal will be submitted to the Eurogroup of finance ministers, who will discuss it during a conference call tomorrow.
It is been confirmed that Greek Prime Minister Alexis Tsipras will make an unscheduled address to the European Parliament tomorrow morning.
This evening's summit was the first time that European leaders came face to face with Mr Tsipras since Sunday's referendum, which saw Greeks reject strict bailout terms.
Earlier, Finance Minister Michael Noonan said he has never taken a 'hard line' against Greece.
Mr Noonan said he hoped a solution could be found - and denied Ireland is being 'tough' on Greece.
“I think I have a lot of witnesses here to show that I have never had a hard line approach to Greece."
“I’ve always said Ireland wants Greece to stay in the euro group and that we prefer to negotiate and we see restructuring of the debt as part of the negotiation,” he said.
Greek banks remain closed
Greece is perilously close to leaving the currency after some 61% of voters rejected a new bailout deal that demanded further austerity measures.
There are fears that banks and cash machines in Greece could run dry if a deal cannot be hammered out in the next few days on its €240bn debt.
As the country enters uncharted territory - no state has ever left the currency - its government backtracked on promises that banks would re-open today.
They will now stay shut until at least Thursday, with a €60 daily limit on ATM withdrawals, that has seen long queues at cash machines, kept in place.
There was some relief on Monday when the European Central Bank (ECB) said it would maintain the Emergency Liquidity Assistance (ELA) Greece needs to keep its banking system afloat.
But the ECB also said it was "adjusting" the conditions - which could make it tougher for some Greek banks to qualify for help.
