Saturday's event, held at the Regent Warsaw Hotel, was chaired by Polish ruling-party chief Jarosław Kaczyński and attended by Hungarian prime minister Viktor Orbán and French presidential contender Marine Le Pen.

It also included Spanish Vox party head Santiago Abascal, Martin Helme from the Estonian Conservative People's Party, and Tom Van Grieken from Belgium's Vlaams Belang, as well as lesser known figures from eight other far-right parties in EU states.

But it did not include Italy's Matteo Salvini, whose League party said "the time needs to be right" to form any new EP family.

It also did not include Austria's FPÖ or Germany's AfD anti-EU parties.

The "Warsaw Summit of Conservative Leaders of Europe" adopted a one-page declaration, which spoke out against "the disturbing idea of creating a Europe governed by a self-appointed elite".

It attacked "arbitrary application of EU law", in a nod to the fact Kaczyński and Orbán were being pursued by EU institutions for abuse of rule of law.

And the summit conclusions attacked EU "social-engineering" designed to "detach a human being from their culture and heritage", mentioning recent EU guidelines to staff, which had encouraged officials to use the word "holiday" instead of "Christmas" in their communications for the sake of inclusivity.

Signatories agreed "closer cooperation of their parties in the European Parliament, including organising joint meetings and aligning votes".

But they did not unveil a new EP group, as they had hoped to, according to earlier Hungarian media reports.

"In the coming months, we'll organise a series of intellectual conferences at the level of experts, professors, various think-tanks ... to prepare our vision," Tomasz Poręba, an MEP from Kaczyński's PiS party, told press.

"We've been working for months to create a strong party family, hopefully we can make a step toward this goal," Orbán said ahead of Saturday's talks.

"We can be optimistic about the launch of this political force in the months to come," Le Pen said.

Le Pen was also filmed laying flowers on a visit to a WW2 memorial site as part of her Polish charm offensive.

But her pro-Kremlin views and the fact her party, in recent years, took millions of euros of Russian money dominated PiS' press briefing this weekend.

PiS has hawkish views on Russia, prompting journalists to ask if Le Pen was a fitting ally.

"I'd like to ask, who is pro-Putinist here? Who represents the interests of Putin, including economic ones?", Poręba asked back in a rhetorical question, referring to Russian president Vladimir Putin.

He then reeled off names of former centre-left and centre-right Austrian, French, and German politicians who were not at the Warsaw meeting with Le Pen and who had taken jobs with Russian firms.

Le Pen "doesn't work for any Russian energy firms, unlike many politicians in the [centre-right] European People's Party [EPP] or the European social-democrats," Radosław Fogiel, the PiS deputy-spokesman, added.

PiS currently sits in the European Conservatives and Reformists group in the EP.

Orbán's Fidesz party sits with nobody after it quit the EPP, while Le Pen and many of the other Warsaw-summit delegates are with the Identity and Democracy group.

If they got together, they would become the third biggest force in the EU assembly.

Salvini had earlier declared the creation of a new eurosceptic EP group in July.