Greek Prime Minister Alexis Tsipras faces a showdown with rebels in his own party and coalition partners as he battles to win support for the third bailout offered by the eurozone leaders.
The terms imposed by international lenders led by Germany in all-night talks at an emergency summit obliged Tsipras to abandon promises of ending austerity.
Instead he must pass legislation to cut pensions, increase VAT, clamp down on collective bargaining agreements and put much of the country's economy in the hands of its creditors.
If the deal falls through, Greece's banks face collapse and the country could finally be forced to leave the euro.
The latest bailout is conditional on Greece passing all the agreed reforms - including raising tax revenue and liberalising the labour market - in parliament by Wednesday.
Finance ministers from all 28 EU countries are holding a scheduled meeting in Brussels later this morning, where they will discuss the situation in Greece.
The Greek Prime Minister has said a deal can be done over the country's future if it what all those negotiating want.
Speaking as he arrived for another day of talks in Brussels Alexis Tsipras said: "I'm here ready for am honest compromise. We owe that the people of Europe who want Europe united and not divided. We can reach an agreement tonight, if all parties want it."
Greek prime minister Alexis Tsipras says the Greek government is to submit a proposal that aims for a socially just and economically viable agreement.
The proposal includes "credible reforms" in return for a commitment to "adequate funding", he said, adding that he wants the process to conclude by the end of the week - with a "final exit to the crisis".
"The discussion was held in a positive atmosphere. The process will be fast, it starts in the coming hours with the aim of concluding it by the end of the week, at the latest," Tsipras told reporters after an emergency summit of euro zone leaders.
"The Greek side will continue the effort, having the strong weapon of the Greek people's verdict ... the vast majority's will for a viable agreement to end the discussion (about a Grexit) and offer the prospect of finally exiting the crisis."
The Greek Prime Minister Alexis Tsipras is currently meeting the German Chancellor Angela Merkel and the French President Francois Hollande, ahead of tonight's emergency summit of eurozone leaders.
Alexis Tsipras, the Greek prime minister, has accused the Eurogroup and the ECB of an "attempt to blackmail the will of the Greek people and to hinder democratic processes".
In a televised speech given yesterday evening, Tsipras promised that this weekend's referendum on whether Greece should accept austerity measures imposed on it by the EU would go ahead.
"One thing remains certain," he said. "The refusal of a [debt payment] extension of a few short days, and the attempt to cancel a purely democratic process is an insult and a great disgrace to Europe’s democratic traditions."
He finished: "The dignity of the Greek people in the face of blackmail and injustice will send a message of hope and pride to all of Europe."
There must be a "viable" solution to Greece's debt crisis, the country's prime minister has said as he arrived for crunch talks with European leaders.
"This is time for a substantial, viable solution that allows Greece to come back to growth within the eurozone with social justice," Alexis Tsipras said as he arrived in Brussels.
Speaking alongside Mr Tsipras, European Commission president Jean-Claude Juncker said there had been progress but added: "We are not there yet".
Greece has to reach a deal with its creditors before a June 30 deadline to repay a 1.6 billion euro (£1.1 billion) loan from the International Monetary Fund (IMF).
Mr Tsipras's left-wing Syriza government has presented new proposals for tackling the crisis which have to be approved before it can gain access to vital bailout funds.
Greek Socialist leader Evangelos Venizelos has rejected joining a coalition led by a leftist party opposed to an international bailout.
However, said he would continue efforts to form a government when he receives a mandate from the country's president.
After meeting with Left Coalition leader Alexis Tsipras, Venizelos said:
Greece's leader of the Left Coalition party Alexis Tsipras has ruled out entering a coalition with the conservative New Democracy party, and said he would try to form a government with other leftist parties.
Speaking after talks with New Democracy leader Antonis Samaris, Tsipras said: