Greece has closed the door on attempts to resolve the bailout crisis by announcing a snap referendum, a senior eurozone minister has said.
Jeroen Dijsselbloem, president of the Eurogroup of finance ministers for the single currency, said he was "disappointed" by the surprise plans to stage a popular vote on debt financing proposals.
Greek prime minister Alexis Tsipras announced in the early hours that the poll would be held on July 5 and the government has said it will campaign for a "No" vote.
The left-wing Syriza leader said proposals put forward by international creditors would place "unbearable" burdens on the Greek people and was a "blackmail ultimatum".
Greeks flocked to cash machines across the country to withdraw money after the referendum announcement was made.
Finance ministers are meeting in Brussels where Greece is asking for a bailout extension as a crucial repayment deadline looms that carries the risk of bankruptcy and could lead to it crashing out of the euro.
Mr Dijsselbloem, the Dutch finance minister, said: "I am very disappointed. After our last meeting, the door on our side was still open, but that door has closed on the Greek side."
Greece needs fresh loans to stop it defaulting when it faces a debt repayment of 1.6 billion euro (£1.1 billion) to the International Monetary Fund on Tuesday. If it fails to meet the deadline it will be declared in default, pushing it towards the exit door from the single currency.
Greek finance minister Yanis Varoufakis said the government wanted to let voters decide.
"We received 36% of the vote. For a momentous decision of this nature we felt the need to secure 50%+1," he said.
IMF head Christine Lagarde said creditors "will continue to work" with Greece and "always showed flexibility" but insisted the country must make "deep" structural reforms to turn around its failing economy.