Greece has submitted "no concrete proposals" for a new bailout, at a key meeting of eurozone finance ministers, Malta's PM says.
Joseph Muscat tweeted that this "doesn't help this evening's eurozone leaders' meeting" in Brussels.
The eurozone had urged Greece to submit fresh plans after its people rejected a new draft bailout in a referendum.
Greek PM Alexis Tsipras is to address the European Parliament on Wednesday, a Greek government source said.
Reports say that the Greek side gave a presentation at the finance ministers' meeting earlier on today. However, sources said there was no new written plan.
One source told Reuters: "They say they will submit a new request and outline of proposals, maybe tomorrow (Wednesday)."
Reflecting the level of difficulty at the meeting, another eurozone official said: "If they really plan to present something formal tomorrow, they may not find anyone to read it."
Mr Tsipras has been reported to want Greece's vast €323bn debt to be cut by up to 30%, with a 20-year grace period.
He will meet German Chancellor Angela Merkel and French President Francois Hollande before this evening's leaders' summit in Brussels, a Greek government official said.
French PM Manuel Valls said earlier that France would do all it could to keep Greece in the eurozone and that "the basis for a deal exists".
However, Germany has warned against any unconditional write-off of Greece's debt, amid fears it would destroy the single currency.