After nearly six years of bailouts and brinkmanship, Greece and its creditors are staring down the barrel of a gun Friday as they face a weekend deadline to seal a reforms-for-rescue deal—or ensure a missed payment by Greece. In what analysts and markets see as the final deadline, Greece has to reach a deal with creditors Saturday or it will fail to make a crucial debt payment due to the International Monetary Fund on Tuesday. On Friday evening, Greek Prime Minister Alexis Tsipras called for a vote on the bailout proposals that he described as unbearable and humiliating. The Eurogroup partners have presented an ultimatum to Greece that is against the values of Europe, he said, according to Reuters. The aim of some of Greece's partners is the humiliation of the people of Greece, he added. In the same announcement, Greek officials said the country's banks will open on Monday and noted that there are no plans for capital controls. Dow Jones reported that the referendum is slated for July 5, which would require a few more days of leeway from the euro zone. Hours after the call for a referendum, reports about long lines for cash machines started appearing on social media. Spiegel tweet Earlier Friday, one official told Dow Jones that the embattled country may not make the Tuesday cutoff—even with a weekend agreement.

After four meetings this week, Greece and its international creditors—the European Commission, the IMF and the European Central Bank—are still no nearer a deal that would unlock desperately-needed funds for Athens.

In fact, some euro zone ministers are against the creditors' current proposal because it goes too easy on Athens, Dow Jones also reported, citing an European Union official. Despite the looming deadline, one official told Reuters that a missed payment (and subsequent arrears status) would not be the end of the world for Greece as long as there is a clear deal. Greece's creditors see limited scope to accommodate Athens in talks on financing for reforms to clinch a deal on Saturday and are willing to reaffirm a 2012 promise to consider rescheduling its debt, a senior official close to the talks told Reuters. To facilitate a deal, the creditors could restate the pledge to help make Greek public debt sustainable by extending loan maturities and a moratorium on interest payments and lowering interest rates. On Friday around midday, a glimmer of hope for Greece was offered by a reported document that said the euro zone could help Greece repay maturing debt in a five-month extension of the current bailout program using money that remains available to Athens. However, the financing note prepared for euro zone finance ministers and seen by Reuters, said that the money could only be disbursed if the Greek parliament approves a deal with creditors and passes the first set of laws on reforms. Read MoreGreek deal Q&A: What's holding things up?

Sure enough, a Greek government official told Reuters the proposed extension and funding package is totally inadequate. The wire service also cited an official saying Athens does not have the mandate to sign onto a new bailout. For his part, Tsipras said the offer to release billions in frozen aid amounted to "blackmail," but he did not rule out a deal. Plus, other media reports emerged that Athens had rejected the extension proposal. The Eurogroup of euro zone finance ministers will meet again on Saturday at 16:00 London time in a last-ditch effort to find an agreement that could release a vital last tranche of bailout aid worth 7.2 billion euros. If a deal was found, however, the Greek parliament would have to approve it too, making time of the essence.

Greek Prime Minister Alexis Tsipras speaks to journalists as he arrives for a emergency summit with European Union leaders in Brussels on Thursday, June 25, 2015. Jasper Juinen | Bloomberg | Getty Images

German Chancellor Angela Merkel told a news conference after the first day of a European Union summit, taking place after the Eurogroup meeting Thursday, that a deal was urgently needed. "We are saying, not without careful thought, that this Eurogroup is of decisive importance, taking into account that time is very short and that a result must be worked on," she said early on Friday, Reuters reported. Whether the Greeks will make any more concessions is uncertain. On Friday, the country's finance minister, Yanis Varoufakis, told Irish Radio that Greece had bent over backwards to accommodate "strange demands" from creditors. He added, however, that his country's commitment to remain in the euro zone was absolute. Late on Friday morning, Tsipras met with Merkel and French President Francois Hollande. Tsipras told his French and German counterparts that Athens could not understand "the institutions' insistence on such harsh measures," according to an unnamed Greek official cited by Reuters.



No more deadlines?

Satyajit Das, a former banker and author of "Traders, Guns & Money: Knowns and Unknowns in the Dazzling World of Derivatives", told CNBC Friday that "nobody believes this is the last chance" for Greece

"We've had so many 'last chances' so nobody actually believes it's the last chance," he told CNBC Europe's "Squawk Box." "Overall, it's going to be a mess but I think there will be some kind of patch up but we'll be back at the table in some months." Other market analysts were preparing for financial turmoil in Greece, however, if no deal was found this weekend, the ECB could then withdraw its emergency liquidity assistance (ELA) to Greek banks, forcing Greece to implement capital controls to prevent bank runs. Read MoreGreece faces hostility at home and abroad

"By the time the markets reopen next week, Greece may have either secured a deal or accepted default to the IMF," Craig Erlam, senior market analyst at currency trading firm OANDA said in a note Friday. "This could prompt a significant reaction in the markets, particularly the default scenario, and see them gap at the open on Monday which can be very concerning from a traders perspective." "While until now people have just assumed the deadline will be pushed back – a relatively safe assumption until now given the tendency to do so – it will be very difficult to do so on this occasion due to Greece's repayment due to the IMF on Tuesday."