ATHENS: Greece and its creditors are locked in a stalemate after loan talks collapsed over the weekend, bringing Athens just two weeks away from a catastrophic default on its debt.

Both sides insisted on Monday they were willing to engage, but without making a decisive step to break the deadlock.

While the European executive insisted the EU-IMF creditors had made "major concessions", the radical left government in Athens continues to reject what it views as "irrational" austerity demands.

The talks concerning the release of the 7.2 billion euros ($8.1 billion) in rescue funds remaining in Greece's bailout have dragged on for five months.

On Monday, hours after Prime Minister Alexis Tsipras defiantly called on the creditors to be "more realistic," Athens said it was ready to return to the talks "at any time".

"We await the invitation of the (creditors) and will respond at any time to continue the negotiation," Tsipras' office said, although it did not say if it was ready to meet the creditors' demands.

The prime minister had earlier lambasted the creditors for "political opportunism".

"One can only see a political purposefulness in the insistence of creditors on new cuts in pensions after five years of looting under the bailouts," Tsipras told Greek newspaper Efimerida Ton Syntakton.

But an EU spokeswoman said the EU and IMF have already made "major concessions" to Greece. "It's not a one-way street," Annika Breidthardt told a press conference.

She added: "The concessions ... made and the flexibility that has been shown are already quite substantial."

In Frankfurt, European Central Bank chief Mario Draghi urged all sides "to go the extra mile" but insisted the ball was in Athens' court.

"A strong and credible agreement with Greece is needed, not only in the interest of Greece, but also of the euro area as a whole," Draghi told the European Parliament's Committee on Economic and Monetary Affairs in Brussels.

And French President Francois Hollande urged a restart of talks "as quickly as possible", warning Greece that it "should not wait".

But Austrian Chancellor Werner Faymann, who has generally been sympathetic to Greece's arguments, said recession-hit Athens' demand for a change of course was "perfectly understandable."

"Greece constitutes a warning on what happens when one applies only austerity," Faymann, who is visiting Greece on Tuesday, told Greek state agency ANA.

The chancellor argued in favor of a five-year plan to "give hope back" to the Greeks.