Greek Prime Minister Alexis Tsipras (L) talks with European Union High Representative for Foreign Affairs Federica Mogherini while attending the family photo session of European Union (EU) summit in Brussels, Belgium, on June 25, 2015. Greek debt crisis, migration and anti-terrosism are expected to top the agenda of the two-day summit. (Xinhua/Zhou Lei)

The leaders of states and governments of the European Union (EU) gathered here Thursday as a parallel crucial Eurogroup meeting on Greece ended abruptly without a deal.

Eurozone finance ministers met earlier on Thursday for their fourth meeting in a week, attempting once again to strike a deal on a package of Greek economic reforms to unlock bailout funds for Athens.

Hopes of a breakthrough fell when the ministers' meeting ended abruptly again.

"No Eurogroup agreement in sight on Greece. Eurogroup meeting has been indefinitely suspended," an EU official said.

With no agreement yielded this afternoon, the focus shifts to the EU leaders who pledged to finalize the process within the week.

"For now, I can only say that work is underway and for sure it will need still many hours," President of the European Council Donald Tusk said ahead of the summit, hinting that there would be an agreement over the issue.

"The last hours have been critical but I have a good hunch that unlike in Sophocles' tragedies, this Greek story will have a happy end," Tusk said.

After marathon talks with creditors on Wednesday, Greek Prime Minister Alexis Tsipras was optimistic about reaching an agreement with his country's creditors.

"I am confident compromise will help Eurozone and Greece overcome the crisis," Tsipras told reporters ahead of the summit.

Greece submitted another version of it's reform proposal before the Eurogroup meeting on Thursday.

Leaders of other EU member states had divergent reactions to the ongoing Greek debt talks before they stepped into the meeting room.

French President Francois Hollande said an agreement was still "possible" and "necessary," while German Chancellor Angela Merkel criticized Greece for "going backwards" on some items.

Talks over the Greek debt issue have been in deadlock for five months. The European Commission, the International Monetary Fund (IMF) and the European Central Bank are unwilling to unlock the final 7.2-billion-euro (8.1 billion U.S. dollars) tranche of bailout funds until Greece agrees to economic reforms.

On June 30, the extension of Greece's second bailout expires. Without a deal by then, Athens may not cover a 1.5-billion-euro loan installment payment to the IMF due by the same day. As a result, the country risks a default and an exit from the eurozone.

An EU source said Merkel urged leaders to find a deal on Greece before markets open on Monday and another Eurogroup meeting is likely to be reconvened on Saturday.