Athens: Greek voters headed to the polls on Sunday to vote in a historic, tightly fought referendum on whether to accept worsening austerity in exchange for more bailout funds, in a gamble that could see it crash out of the euro.

Across the country of 11 million people—on far-flung Aegean islands, in the shadow of the 2,400-year-old Parthenon in Athens, to the northern border shared with fellow EU state Bulgaria—voters began casting their ballots.

The rest of Europe, and international investors, will be watching intently, unsure of the outcome that could greet them on Monday. Polls suggest both the ‘Yes’ and ‘No’ camps are neck-and-neck.

Dozens of people were queuing outside schools and university buildings transformed into polling stations, with doors opening sharply at about 7:00am local time (0400 GMT) and set to close 12 hours later.

Greece’s youthful Prime Minister Alexis Tsipras, a radical leftist who came to power six months ago, has staked his political career on the plebiscite.

He announced it a week ago in a bid to break a five-month impasse with international creditors, insisting a ‘No’ vote would force a restructuring of Greece’s massive debt and a softening of drastic austerity conditions.

Supermarkets emptied

But many who first backed him have swung to the ‘Yes’ camp, heeding warnings from EU leaders, notably European Commission chief Jean-Claude Juncker, that a ‘No’ result could see Greece expelled from the 19-nation eurozone—a so-called “Grexit”.

Greece was officially declared in default on Friday by the European Financial Stability Facility, which holds 144.6 billion euros ($160 billion) of Greek loans, days after becoming the first developed country to miss a debt payment to the IMF.

Tsipras’s flamboyant finance minister, Yanis Varoufakis, on Saturday accused Athens’s creditors of “terrorism” for trying to sow fear around the vote.

He pointed out that no legal mechanism exists to force Greece out of what is meant to be an “irreversible” monetary union.

Greeks were nevertheless alarmed this week when the government imposed capital controls, closing banks and limiting daily ATM withdrawals to just 60 euros ($67).

The banks’ liquidity was expected to dry up entirely in just one or two days’ time unless the European Central Bank (ECB) injected funds quickly.

Supermarket shelves have been emptied in the days leading up to the referendum.