Euro zone leaders will tell Greece on Thursday that time and patience are running out for its leftist-led government to implement agreed reforms to avert a looming cash crunch that could force it out of the single currency.

Greece has been kept from bankruptcy by two international bailouts but now risks running out of money within weeks if it does not receive more funds. Greek banks reported the largest deposit withdrawals in a month, a sign savers are worried about the outlook for the country's finances and institutions.

Prime Minister Alexis Tsipras has requested a meeting with the leaders of Germany, France and the main EU institutions on the sidelines of a European Union summit to press for Athens to receive short-term funds to keep itself afloat.

"I will repeat to him what I’ve already told him twice: Greece must undertake the necessary reforms, Greece must ensure that the commitments it made to the Eurogroup in 2012 and more recently are followed up on," European Commission President Jean-Claude Juncker told France's Europe 1 radio.

German Chancellor Angela Merkel delivered the same message in a speech to parliament ahead of the late-night Brussels talks and a crucial visit by Tsipras to Berlin next Monday, saying the crisis could only be overcome if Greece stuck to agreements.

No one should expect a solution from Thursday's session or her meeting with Tsipras next week, which offered "time to talk to each other in detail and perhaps also to argue", she said.

A political meeting of a small group of leaders could not be used to circumvent the formal agreement Greece concluded on Feb. 20 with Eurogroup finance ministers, she told the lawmakers.

"There remains a very tough way ahead," Merkel said. Greece must understand that international aid brought with it an obligation "to reform its budget and work towards one day no longer needing help".

European Council President Donald Tusk, who will chair the summit, said he arranged a side-meeting with Tsipras to take the heat out of exchanges around the main table. It would, however, not be decisive as leaders would go on trying to avoid Greece being inadvertently shut out of the euro -- a "Grexident".