EU President Donald Tusk today urged euro zone finance ministers to meet on debt-hit Greece within days, but did not immediately grant Prime Minister Alexis Tsipras's request for an emergency summit. 

"We need a specific date for the new Eurogroup meeting in the not so distant future, and I am not talking about weeks but about days," Tusk told reporters in Brussels.

"We have to avoid a situation of renewed uncertainty for Greece," he added. 

The Greek Prime Minister Alexis Tsipras wanted an EU summit to help facilitate negotiations with the debt-ridden country's creditors.

This comes after a meeting of euro zone finance ministers, mooted for Thursday, was postponed.

Eurogroup chief Jeroen Dijsselbloem said that "more time" was needed to decide on the next steps for Greece's massive bailout.

Dijsselbloem, the Dutch finance minister, had said earlier that a meeting could take place on Thursday "to finalise as many things as possible" in unlocking bailout cash and triggering potential debt relief for Greece.

Debt-crippled Greece still needs to deliver crucial reforms in order to unlock more cash from its massive €86 billion bailout plan.

Meanwhile, Greece has accused the International Monetary Fund of undermining negotiations over the release of more bailout funds needed in the next few weeks to repay debt.

At issue is what measures Athens would take if it fails to reach fiscal targets by 2018. Creditors, including the IMF and European institutions, want those measures made law immediately.

Athens argues that its constitution precludes legislation on a hypothetical event but it has offered to discuss a mechanism of automatic cutbacks.

Government spokeswoman Olga Gerovasili told reporters that the IMF had not accepted the proposal.

"The IMF is making demands which go beyond what was agreed," Gerovasili said, referring to a €86 billion deal struck last year and talks to unlock more than €5 billion in bailout funds needed to pay EU and IMF debts by July.

"These demands undermine efforts by both the Greek government and European institutions," she said.

An IMF spokesman in Washington said the institution had no immediate comment on the matter.