Greek left-wing leader Alexis Tsipras
Greek left-wing leader, Alexis Tsipras has accused the EU and German Chancellor Angela Merkel of "playing poker with European people's lives" by insisting on austerity measures, reports the BBC.
Mr Tsipras' Syriza bloc is predicted to come first in new elections called for 17 June. Syriza wants to renegotiate Greece's international bailout.
At least 700m euros (£560m; $890m) was withdrawn from Greek banks in the week until Monday, the Greek president said.
But there are no signs of a bank run.
In a BBC interview, Tsipras said if the "disease of austerity destroys Greece, it will spread to the rest of Europe".
Banks were profiting at the expense of thousands of Europeans - in Spain and Italy, as well as Greece - left in poverty and hardship, he said.
"Therefore the European leadership and especially Mrs Merkel need to stop playing poker with the lives of people," Tsipras said.
Syriza came second in inconclusive elections on May 6, in which no party won a majority or was able to form a coalition.
Syriza refused to join any government which would continue with the austerity measures demanded by the EU and International Monetary Fund (IMF) in return for a bailout of 130bn euros ($170bn; £105bn).
Final talks to form a government failed on Tuesday, raising new concerns over Greece's eurozone future.
Council of State president and judge Panagiotis Pikrammenos has been sworn in as interim prime minister to head a government until the elections next month.
"It is clear to all that our homeland is going through difficult times," Pikrammenos said after accepting the mandate from President Papoulias.
"We must safeguard its prestige and assure a smooth transition."
He joked that he had read in the press that the English translation of his name was "embittered" - making him suited to be the last prime minister of a political era.
The rest of the government will be sworn in on Thursday.
"[Greek central bank chief, George] Provopoulos told me there was no panic, but there was great fear that could develop into a panic," President Karolos Papoulias was quoted as saying in minutes of talks on Tuesday with the political parties.
The Financial Times newspaper quotes Athens-based bankers as saying withdrawals exceeded 1.2bn euros on Monday and Tuesday - 0.75% of deposits.
Jose Manuel Barroso, President of the European Commission: "Don't abandon the eurozone"
However, there were no signs of panic or queues outside banks in Athens on Wednesday.
European Central Bank (ECB) Governor Mario Draghi and Spanish Prime Minister Mario Rajoy both said on Wednesday they wanted Greece to remain in the euro.
"I want to state that the governing council's strong preference is that Greece will continue to stay in the euro area," Draghi said.
The Governor of the Bank of England, Sir Mervyn King, warned that the eurozone was "tearing itself apart" and the UK economy would not escape "unscathed".