Greece says deal on debt crisis unlikely at Thursday talks

On Wednesday Andreas Scheuer, the secretary-general of the CSU party, said the Greek government had not "realised the seriousness of the situation yet".

In an interview with Rheinische Post newspaper he said: "They are behaving like clowns sitting in the back of the classroom, although they have received explicit warnings from all sides that they might fail to pass to the next grade."

Greek savers pulled out some 2 billion euros between Monday and Wednesday after weekend negotiations collapsed in Brussels, senior banking sources told Reuters. That is double the amount that the European Central Bank granted Greek banks in extra emergency liquidity assistance (ELA) this week.

Asked at the meeting whether Greek banks would be open tomorrow, ECB Executive Board member Benoit Coeure said: "Tomorrow, yes. Monday, I don't know," according to officials with knowledge of the talks.

The IMF dashed any hope that Athens could avert default if it fails to repay a 1.6 billion euro ($1.8 billion) loan by the end of June, piling pressure on Prime Minister Alexis Tsipras, who shows no sign of yielding to the lenders.

If deposit flight continues to outpace ELA, it could force Greece to impose capital controls, as Cyprus did in 2013, to ration cash withdrawals and stop money fleeing the country.

IMF Managing Director Christine Lagarde said further dialogue was needed "with adults in the room".