Eurozone finance ministers have rejected a Greek request to extenda bailout programme beyond 30 June.
A Eurogroup statement said Greece had broken off negotiations over a new bailout deal "unilaterally".
Late on Friday, Greek PM Alexis Tsipras called a surprise referendum for 5 July over the terms of any new deal.
Greece has to pay €1.6bn (£1.1bn) to the IMF on Tuesday. Without new funds, there are fears Greece may leave the euro and its economy may collapse.