Greece's borrowing costs in the markets rose rapidly, as fears of a Greek debt default weighed.
Greek three-year bond yields jumped more than than 3.5% to about 27%.
The yield on Greece's 10-year bonds rose a percentage point to 13%.
Greece had made an "informal approach" to the International Monetary Fund to have its bailout repayments delayed, but had been rebuffed, as the Financial Times has earlier reported. Greece owes the IMF some €1bn in repayments next month. Meanwhile analysts wonder have soon 'informal' talks could turn into serious delays and missed payments as Greece rapidly runs out of cash.
Market players mostly consider that the Greek government will struggle to make those payments if it does not make an agreement on an economic reform package with European creditors soon.
The country will default if it fails to agree a plan with creditors. This could force the government to put limits on money transfers and even lead the country to leave the euro. Meanwhile, BBC economics editor Robert Peston considers Greece does not necessarily need to leave the euro if it misses a debt payment.
The EU was "not satisfied with the level of progress made so far" in debt negotiations, according to EU spokesman Margaritis Schinas. German Finance Minister Wolfgang Schaeuble also warned an agreement between Athens and its creditors is not likely in the next week.
"The government could follow the example of Cyprus and impose restrictions on the export of capital from the country, to conserve as much cash as possible in a banking system too close to collapse for comfort," he said.
"And it could create its own IOUs, a sort of parallel domestic currency interchangeable with euros, to pay its employees and trade creditors."
Yesterday ratings agency S&P downgraded Greece's credit rating to CCC+.
