The European Commission said Sunday that weekend talks to find common ground between international creditors and Greece were unsuccessful and left a wide rift that needs to be closed within two weeks to avoid a possible Greek default, ABC News reported.

An EU Commission official, who refused to be identified because of the sensitivity of the negotiations, said that "the talks did not succeed as there remains a significant gap between the plans of the Greek authorities and" the demands of the international creditors.

On top of that, the official said that, for the EU's executive, "the Greek proposals remain incomplete." The official refused to be more precise.

European Commission President Jean-Claude Juncker "remains convinced that with stronger reform efforts on the Greek side and political will on all sides, a solution can still be found before the end of the month," the official said.

Finance ministers from the 19 nations using the euro currency have a meeting next Thursday in Luxembourg which has already been billed as decisive to see if a bailout deal for Greece can be found.

Without outside help, Greece is unlikely to be able to repay a roughly 1.6 billion-euro IMF debt installment due June 30 and larger debts due to the European Central Bank in July and August.