EU leaders said Thursday they would intensify efforts to convince Hungary's Viktor Orban and Poland's Mateusz Morawiecki to drop their veto of the EU coronavirus economic recovery plan, which has plunged the bloc into a new crisis threatening joint efforts to fight the epidemic.

The bloc's 27 heads of state and government spent fewer than 15 minutes on the issue at the start of a video summit, with German Chancellor Angela Merkel, who holds the EU's rotating presidency, responding to the rebels on their behalf.

"This is of course a very serious problem, which we have to solve," Merkel told reporters after the meeting. "We want to work, we want to sound out all options that would be possible and we are still at the very beginning."

Warsaw and Budapest, with the support of Slovenia, threw the EU into turmoil this week by using their veto to block the EU's combined 1.8-trillion-euro ($2.1 trillion) post-virus recovery plan and long-term budget.

While not a complete surprise, the stand-off angered EU partners, with many keenly awaiting payouts from the stimulus to help fix economies shattered by the pandemic and worse feared to come.

But an EU official said EU Council President Charles Michel, who hosts European summits, made sure ahead of time that the conversation would remain short and "under control" to allow for later mediation.

"The three naysayers reiterated their reasons for their opposition, without any fresh or new nuance," another senior EU source told reporters.

The nationalist governments are furious at their EU partners for backing a decision that ties the disbursement of bloc funds to respect for the rule of law and European values.

Morawiecki and Orban are frequent scourges of Brussels, with anti-EU rhetoric rife in both their governments despite Hungary and Poland being the biggest receivers of bloc spending.

"Hungary and Poland stated what they didn't want, not what they did -- true to their form as men of trouble, not of solutions," said an irritated European diplomat.

Poland's Prime Minister Mateusz Morawiecki (L) and Hungary's Prime Minister Viktor Orban have accused the EU of mounting a power grab
Poland's Prime Minister Mateusz Morawiecki (L) and Hungary's Prime Minister Viktor Orban have accused the EU of mounting a power grab POOL / FRANCOIS LENOIR

The plan to tie EU funds to the rule of law, strongly defended by the European Parliament and most member states, has the votes to be approved by a qualified majority of members.

But Hungary and Poland are fighting back by using their veto against allowing the EU to raise funds to finance its 750-billion-euro recovery plan and against the trillion-euro 2021-2027 budget, which require unanimity.

"Where does it stop?" Poland's Morawiecki demanded of his EU counterparts, according to a source with knowledge of the proceedings.

"You are using this only against us and circumventing the treaty," Morawiecki reportedly said. Before the summit he had slammed an alleged "European oligarchy" that was trying to bully weaker EU members.

The rule-of law issue is hugely sensitive for both countries. Poland is already under an EU investigative procedure over its efforts to trim the independence of the judiciary, as is Hungary for an erosion of democratic norms, such as press freedom, under Orban's rule.

The rest of the bloc had hoped that the matter had been settled in July after a four-day and night summit hammered out an apparent budget compromise.

"Blocking the adoption of a decision on the recovery plan negatively affects the whole EU, including the citizens of Hungary and Poland," Romanian Prime Minister Ludovic Orban -- no relation to Viktor Orban -- told AFP.

Germany, which holds the EU presidency until December 31, will work furiously behind the scenes to defuse the row, and some diplomats think Orban and Morawiecki could be persuaded quietly to accept guarantees of fair treatment.

"There was nothing to discuss at this political level, it's too early. They want the discussions happening at a lower level," said analyst Eric Maurice, of the Schuman foundation.

France and the Netherlands have invoked the possibility, seen as implausible by many, of by-passing the log-jam by pushing ahead with an intergovernmental recovery plan, without the holdouts.

"The magic of European Union is to succeed in finding solutions, even when you think it's going to be impossible," Michel said after the talks.