The EU on Monday pressed Greece to match the major concessions made by its international creditors in order to reach a deal that will save Athens from default.
The European Commission, the EU executive, also said Greece has agreed to budget targets for 2015, but then asked "how credible the commitments are" to achieve them.
"It's not a one-way street," commission spokeswoman Annika Breidthardt told a press conference after saying the EU-IMF creditors have made "major concessions" to the left-wing government in Athens.
She added: "The concessions ... made and the flexibility that has been shown are already quite substantial."
Talks between Greece and its EU-IMF creditors ended with no deal on Sunday, setting the countdown towards a disastrous default by Athens with the threat of a Greek exit from the euro closer than ever.
All sides had agreed that the talks were the last chance for Athens to unlock vital bailout cash by the end of the month, in return for tough reforms that Greek Prime Minister Alexis Tsipras still doggedly refuses to agree to.
"The package proposed by the institutions is substantial. It is balanced and it makes full economic sense," Breidthardt said.
"The proposals meet the need of the Greek people, the Greek government but also of the other 18 member states who also are democratically accountable," she said.
Greece is a member of the 19-country eurozone.
The central question dividing the two sides is the state of Greece's budget, with fears high that Athens is again running a deficit, spending more public money than it receives.
But the EU and IMF are asking for a primary surplus target of one percent of annual GDP for this year, a measurement that excludes the cost of servicing Greece's debt.
"The Greek authorities agreed to this target, the question is how credible the commitments are to achieve (them)," Breidthardt said.
In Madrid meanwhile, Spanish foreign minister Jose Manuel Garcia-Margallo said Greece runs a "real risk" of crashing out of the eurozone.
"That would not be good for Europe and it would of course be very bad for the Greek people," the minister said.