Greece's main stock index fell 4.5 percent Friday amid uncertainty over the radical government's reform plans and its ability to meet its financing needs.
The Athens stock exchange was down to 863 points as the government raced to find over 1.5 billion euros ($1.7 billion) to pay the International Monetary Fund next month.
Greek Finance Minister Yanis Varoufakis said Friday in an Antenna TV interview that "at this moment the coffers are empty."
The government hopes that the European Central Bank will rescue Greece by handing over 1.9 billion euros in profits made on Greek bonds.
"The ECB could simply hand over this money to the IMF," Varoufakis told Bloomberg TV earlier this week.
"I find it very hard to imagine that Europe and the IMF will allow us to trip over what is a relatively small cash problem," he told Bloomberg TV.
The ECB has previously handed back to Athens any profit it made on purchases of Greek government bonds.