Last Updated Jul 3, 2015 1:15 PM EDT
ATHENS, Greece -- Rival campaigns in Greece's bailout referendum are heating up Friday, with simultaneous rallies in Athens for "Yes" and "No" supporters.
Brief clashes broke out between a group of youths and police in the Greek capital's Syntagma Square just before the start of the main "No" rally backed by Prime Minister Alexis Tsipras' government.
Greek police used pepper spray Friday evening to deter several dozen anti-establishment protesters from throwing rocks and smashing property in the big Athens square in front of parliament.
The 'Yes' side was holding its rally just 800 meters away in a different section of central Athens.
The events culminate a five-day campaign on one of the most important votes in Greece's modern history that still has many voters confused about about what's at stake.
Costas Christoforidis, a 37-year-old farmer, hasn't decided how to vote Sunday.
"If it's saying 'No' to austerity, then it's a 'No' from me too. But if we are rejecting Europe, I disagree with that," he said.
His opinion is echoed by a recent ALCO poll of 1,000 Greek citizens conducted for To Ethnos newspaper.
The poll found that although roughly 40 percent of citizens are against austerity, 74 percent want to remain with the Euro and 15 percent want a national currency.
But European and Greek opposition leaders have signalled that a vote against reform is tantamount to a Greek exit from the Eurozone.
"The consequences are not the same if it's a 'Yes' or 'No,'" French President Francois Hollande said.
"If it's the 'Yes,' even if it's on the basis of proposals that have already expired, negotiations can resume and I imagine be quickly concluded," he said. "We are in something of an unknown. It's up to the Greeks to respond."
Tsipras, the popular 40-year-old prime minister, is gambling his government on a call to voters to reject austerity measures demanded by bailout lenders, despite coming close to a deal last week.
"Our efforts are focused on overcoming the crisis as fast as possible - with a solution that preserves the dignity and sovereignty of our people," Tsipras said.
A strong "No" vote, he argued, would help Greece win a new deal with the eurozone's rescue mechanism that would include terms to make the country's 320 billion euro national debt sustainable.
After the vote, he insisted, a deal could be struck "within 48 hours."
Opponents don't believe him and say he is risking the country's future - asking voters to weigh in on a bailout offer that expired at midnight on Tuesday.
"They are making a serious mistake. Because the world will consider a 'No' vote to be a withdrawal from the heart of Europe - the first step toward euro exit," former conservative prime minister Costas Karamanlis said, making his first public speech in six years to endorse the "Yes" campaign.
Tsipras' argument was also dismissed by the head of the eurozone finance ministers' group, Dutch Finance Minister Jeroen Dijsselbloem.
"That suggestion is simply wrong," Dijsselbloem told lawmakers in the Netherlands.
And in one of the clearest signs yet that the future of the government is on the line in Sunday's vote, Greece's outspoken finance minister, Yanis Varoufakis, told Australia's ABC radio he was likely to resign if a "Yes" vote prevails.
Tsipras signaled the same earlier this week, declaring on state TV that he was not an "all-weather" prime minister - a strong indication he would step down if his proposal is defeated.
As most Greek banks and markets remain closed Friday for a fifth day, a prediction from the International Monetary Fund that Greece will need piles of additional cash from eurozone countries and others over the next three years put even more pressure on the government.
Tension surrounding the vote has remained high since most banks closed this week and were forced to impose strict cash withdrawal limits.
Elderly Greeks, some struggling with walking sticks or being held up by others, have been forming large crowds outside the few banks opened to help pensioners without ATM cards get access to money.
In Athens, opposing campaigners battled for visibility as time to reach voters was running out. "Yes" posters appeared for the first time around the city, while TV ads only began airing a day earlier. The two main rival rallies are scheduled in central Athens at 7:30 p.m.
The ALCO opinion poll found that voters are split on the actual question that the referendum is asking them to vote on: whether they should accept a bailout and financial reform or reject the plan.
The poll found that 41.5 percent plan on voting for the bailout and 40.2 percent of respondents said they would vote "No." 10.9 percent are undecided.
Some 6,000 supporters of the Greek Communist Party late Thursday attended a rally outside parliament. The party urged voters to cast invalid ballots in protest of Greece's continued membership in the European Union.
The country has been thrown into financial limbo after missing a massive IMF repayment this week when its bailout program expired.
Raising the stakes further for Sunday's vote, an IMF report released Thursday but compiled last week before the talks collapsed, warned that to avoid financial collapse, Greece would need additional debt relief costing 50 billion euros ($56 billion) and lasting through 2018 - a bleak prospect for a country that has already endured six years of recession.
Ashkoda Mody, a visiting professor in international economic policy at Princeton University, argued the IMF's call for debt relief should have been made far earlier, before the talks collapsed.
"If the IMF and other creditors had this document while they were negotiating with the Greeks, it is completely unconscionable that they did not discuss deep debt relief," he said.
Trying to decide how she would vote, 64-year-old retiree Eleni Maili said: "I can't vote 'Yes' or 'No' - both have their pitfalls. And in the end, the lenders will just interpret the result in a way that suits them."
She did have one question of her own, though.
"I do wonder about all that money we got over all those years," she said. "Where is that money? Because the people didn't see any of it."