Rome - They may be celebrating a string of far-right victories in Europe, but Giorgia Meloni and Marine Le Pen have yet to iron out differences stopping them forming a united front.

The heads of the most voted-for parties in Italy and France -- two of the founding countries of the European Union -- will have to wait for the result of France's snap elections on July 7 to determine their game plan.

"There are important differences between their two parties, notably regarding the war in Ukraine," Marc Lazar, a professor at Sciences Po in Paris and the Luiss University in Rome, told AFP.

"I think there will be some kind of more noticeable rapprochement" between them following the French snap legislative election if that vote further strengthens Le Pen, he added.

But Meloni shows signs of wanting to keep the RN at arms' length -- and for now, divisions between the two far-right camps in Europe are marked.

In the parliament they remain divided into two groups -- the European Conservatives and Reformists (ECR) and the Identity and Democracy (ID) group.

After Sunday's EU elections, nationalist and far-right parties from Germany and the Netherlands to Austria and Greece now hope to have greater influence within the bloc.

But on paper the balances of power have not radically changed, with the far-right pocketing a modest increase in seats in the European Parliament -- up from 118 to 131 out of 720, according to estimates.

They may, however, be able to count on some 50 MEPs who share their values but do not belong to either group.

And the centre-right European People's Party (EPP) and its allies, which retain a big majority despite losses in France and Germany, will have to compromise.

"They will certainly have to send signals to European voters on issues which were raised by these (far-right) parties, in particular on two issues: immigration and the green pact", said Lazar.

- One hive, two queens -

The ECR's members of parliament belong to Meloni's Brothers of Italy, the Spanish Vox party, Poland's nationalist Law and Justice (PiS) and Eric Zemmour's far-right Reconquete from France.

ID includes Italian Deputy Prime Minister Matteo Salvini's League party and the RN, but recently excluded Germany's scandal-ridden AfD party.

The ECR and ID have significant differences: ECR supports aid for Ukraine as it fights off the Russian invasion while ID has a more hands-off approach to the conflict.

Meloni, leader of Italy since October 2022, currently has a clear lead over Le Pen in terms of influence over European affairs.

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European Commission chief Ursula von der Leyen, who is running for a second term, has suggested her centre-right EPP may be open to an alliance with the ECR and pro-European, pro-Ukraine Meloni.

She has made no such overtures to ID, which she has described as Russian President Vladimir "Putin's Puppets".

While Le Pen has voiced the idea of a grand far-right group within the EU, Meloni is more wary.

"A hive cannot have two queens", Daniele Albertazzi, co-director at the Centre for Britain and Europe think tank, told AFP.

Meloni does not want to risk her new diplomatic "respectability" by forming an alliance with a group which until a few weeks ago included scandal-hit AfD, he said.

Meloni "will keep trying now to play the game with the big guys.

"She wants to be seen as a modern leader when it comes to foreign policy, Europe, the US," he added.

Meloni hailed RN's success Monday, saying in a radio interview that Le Pen's political journey was "very interesting".

But she suggested the French party benefitted largely from the weakness of its opponents.

"Government parties suffered almost everywhere, except here."

By Gaël Branchereau

Infographic by Valentina Breschi, Guillermo Rivas Pacheco