BRUSSELS (AFP) - Euro zone finance ministers' talks broke up without an agreement on a Greek debt deal on Thursday, Finland's Alexander Stubb said, with sources saying they were likely to meet again on Saturday.

"That's it for today. Institutions and Greece to continue work. Eurogroup back later, but not today," Stubb tweeted after the talks in Brussels, which had been expected to thrash out a deal for EU leaders to approve at a summit opening later Thursday.

The finance ministers were likely to meet again on Saturday, three EU sources said.

The 19-country currency union's finance ministers met on both Wednesday and Thursday in parallel with talks between Greek Prime Minister Alexis Tsipras and the leaders of the European Commission, European Central Bank and International Monetary Fund.

The Tsipras-EU-IMF talks ended earlier Thursday, not only having failed to reach a breakthrough but also producing two rival reform plans which Greece and its international creditors presented separately to the Eurogroup.

Greece's outspoken Finance Minister Yanis Varoufakis confirmed the talks would continue, saying his counterparts had closely compared the two versions.

"Interestingly, several colleagues disagreed and criticised not only our text but also the text of the institutions," he said.

"We decided that as a Eurogroup that we shall continue our deliberations, the institutions are going to look again at the two documents, our documents and their own, in discussions with the Greek government, and we'll continue until we get a solution."

Tsipras said as he arrived at the summit of all 28 European Union leaders on Thursday he was "confident we'll reach a compromise."