Last Updated Jul 13, 2015 7:39 AM EDT
BRUSSELS -- A summit of eurozone leaders reached a tentative agreement with Greece on Monday for a bailout program that includes "serious reforms" and aid, removing an immediate threat that Greece could collapse financially and leave the euro.
Nine hours after a self-imposed deadline passed, the leaders announced the breakthrough early Monday.
If the talks had failed, Greece could have faced bankruptcy and a possible exit from the euro, the European single currency that the country has been a part of since 2002. No country has ever left the joint currency, which launched in 1999, and there is no mechanism in place for one to do so.
As CBS News correspondent Holly Williams reports, the final amount of the bailout taking shape has yet to be agreed, but it is believed Greece needs in the region of $90 billion to avoid financial collapse.
For three days of negotiations between Greece and its international creditors, Greek Prime Minister Alexis Tsipras held out for a better deal to sell to his reluctant legislature in Athens this week, even though financial collapse is getting closer by the day.
A breakthrough came in a meeting of Tsipras, German Chancellor Angela Merkel, French President Francois Hollande and EU president Donald Tusk. Details were not immediately available, but Merkel told reporters eurozone nations were willing to give Greece debt relief but had ruled out a cut in the country's debt level.
The breakthrough came after the threat of expulsion from the euro put intense pressure on Tsipras to swallow politically unpalatable austerity measures because his people overwhelmingly want to stay in the eurozone.
"Advantages clearly dominate disadvantages," Merkel said of the tentative deal. "The basic principles which we always followed to rescue the euro are there, namely on the one side, solidarity among member countries, and on the other side, the responsibility of the country where changes need to take place."
Merkel said the agreement had been reached "despite the recent loss of the most valuable currency; namely trust in each other... Our paper states at the top that trust has to be restored, that those responsible in Greece must take responsibility to implement everything we decided here."
The deal on the table appeared to include commitments from Tsipras to push a drastic austerity program including pension, market and privatization reforms through parliament by Wednesday, and from the 18 other eurozone leaders to start talks on a new bailout program.
"Euro summit has unanimously reached agreement. All ready to go for ESM programme for Greece with serious reforms and financial support," European Council President Donald Tusk tweeted, according to the Reuters news agency, referring to the European Stability Mechanism bailout fund.
However, the tough conditions imposed by international lenders led by Germany could bring down Tsipras' leftist government and cause an outcry in Greece, Reuters says. Even before the final terms were known, his labor minister went on state television to denounce the terms, Reuters reports.
Greece has requested a three-year, 53.5 billion-euro ($59.5 billion) financial package, but that number grew larger by the tens of billions as the negotiations dragged on and the leaders calculated how much Greece will need to stay solvent. The creditors are demanding tough austerity measures in exchange for Greece's third bailout in five years.
Early Monday, a Greek official said the key sticking points were the involvement of the International Monetary Fund in Greece's bailout program and a proposal that Greece set aside 50 billion euros ($56 billion) worth of state-owned assets in a fund for eventual privatization.
The official, who spoke on condition of anonymity because he wasn't authorized to discuss the negotiations, said any agreement would provide quick help for Greek banks from the European Central Bank. Without it, they risk running out of money this week.
The negotiations began Saturday with a meeting of finance ministers. The heads of state convened mid-afternoon Sunday and were still negotiating at dawn Monday.
Sunday's four-page discussion paper put to eurozone leaders and obtained by The Associated Press spoke of a potential "time-out from the euro area" for Greece if no agreement could be found.
It highlighted the increasing frustration of European leaders during five months of fruitless talks with Greece.
"The most important currency has been lost: that is trust and reliability," Merkel said.
Tsipras insisted his government was ready to clinch a deal.
"We owe that to the peoples of Europe who want Europe united and not divided," he said. "We can reach an agreement tonight if all parties want it."
Hollande insisted it was vital to keep Greece in the euro and said in the event of a departure, "it's Europe that would go backward. And that I do not want."
Greece has received two previous bailouts, totaling 240 billion euros ($268 billion), in return for deep spending cuts, tax increases and reforms from successive governments. Although the country's annual budget deficit has come down dramatically, Greece's debt burden has increased as the economy has shrunk by a quarter.
The Greek government has made getting some form of debt relief a priority and hopes that a comprehensive solution will involve European creditors at least agreeing to delayed repayments or lower interest rates.
Greek debt stands at around 320 billion euros ($357 billion) - a staggering 180 percent or so of the country's annual gross domestic product. Few economists think that debt will ever be fully repaid. Last week, the International Monetary Fund said Greece's debt will need to be restructured.