European Council President Donald Tusk said he has canceled an European Union summit originally scheduled for Sunday afternoon, and leaders of 19 eurozone countries will meet at 1400 GMT Sunday to discuss Greece's debt issue.

"I have canceled EUCO today. EuroSummit to start at 16h and last until we conclude talks on Greece," Tusk wrote on his official twitter account.

Without a debt deal, Greece faces a financial collapse and exit from EU.

The Eurogroup held a meeting on Greece crisis on Saturday, but it ended without a deal.

"We have had an in-depth discussion of the Greek proposals. The issue of credibility and trust was discussed, and also of course the financial issues involved," Eurogroup head Jeroen Dijsselbloem said after the meeting, describing the negotiations as "very difficult."

The Eurogroup resumed talks on Greece crisis Sunday morning.