Greece needs to clinch a deal with its EU-IMF creditors at a eurozone meeting on June 18 to prevent it from defaulting on its debt, two ministers said on Friday, a day after the IMF pulled its team out of the negotiations.
Defence Minister Panos Kammenos said in an interview with Mega channel that a deal "will come about by June 18 or never".
Minister of State Alekos Flambouraris, a close associate of Prime Minister Alexis Tsipras, told state television ERT: "I hope (an agreement) comes very soon, on June 18, when the Eurogroup convenes."
Athens stocks slumped four percent at open as optimism a day earlier for an imminent deal evaporated.
Greece needs to find 1.6 billion euros ($1.8 billion) to repay to the International Monetary Fund by the end of the month.
It therefore needs to clinch a deal to unlock 7.2 billion euros in bailout funds by the end of June before its current EU-IMF rescue programme expires, leaving the cash-strapped country with no means of support against a looming default.
Kammenos -- whose populist Independent Greeks party is the junior government coalition partner and is not involved in the talks -- said Friday the IMF payment would not be made if the talks founder.
"If a solution is not found by the end of the month, we will not pay the IMF," he said.
The five-month talks are stuck on disagreement between Greece and its creditors on its future budget goals, economic reforms and tax revenue.
Athens is facing mounting pressure, with the IMF saying Thursday there remains big gaps between both sides and the EU warning the Greeks to stop "gambling" with the possibility of default and a messy exit from the eurozone.
"There are still major differences between us in most key areas," IMF spokesman Gerry Rice told reporters in Washington. "There has been no progress in narrowing these differences recently. Thus we are well away from an agreement."
The fund said its Greek talks team had returned to Washington from Brussels and that the "ball is very much in Greece's court right now" -- although it added that "the IMF never leaves the table and remains engaged."
European Commission chief Jean-Claude Juncker said Tsipras would have to face down his anti-austerity party, where a number of cadres have proposed early elections if forced to accept unpopular cuts.
"This is not a real party but a group of movements, tendencies, sentiments and resentments," Juncker told France Culture radio.