While the Warsaw meeting fell short of creating the new alliance nationalist leaders were hoping for, Le Pen said it marked "a key step" toward closer cooperation.
Leaders of European nationalist parties on Saturday vowed to align their votes on sovereignty and immigration issues in the European Parliament but fell short of creating a formal alliance at a conference in Warsaw.
Hungarian Prime Minister Viktor Orban, French far-right leader Marine Le Pen and the host, Jaroslaw Kaczynski, head of Poland's ruling right-wing populist Law and Justice (PiS) party were among the leaders at the talks.
In a joint statement, they rejected the notion of "a Europe governed by a self-appointed elite" and said that "only the sovereign institutions of the states have full democratic legitimacy".
"The participants also discussed closer cooperation of their respective parties in the European Parliament," the statement said.
This would include "organising joint meetings and aligning the votes on common issues, such as protection of sovereignty of the member states and the stance on illegal immigration," it added.
'We want to change the politics of Brussels'
The meeting aimed to bring change to the European Union, which nationalist and populist parties accuse of undermining sovereign nation-states.
"We want to change the politics of Brussels," Hungarian Prime Minister Viktor Orban wrote on Facebook ahead of Saturday's meeting.
Around a dozen activists protested outside as the talks got underway, shouting "No to fascism!".
The meeting follows a visit by Le Pen to Budapest in October that was part of an effort by her and Orban to consolidate the European right.
It also comes as both the Polish and Hungarian governments remain locked in a bitter standoff with the EU, which is withholding funds to both countries over democratic backsliding.
Towards a group at the European parliament?
Le Pen, a candidate in France's presidential election in April, said the meeting in Warsaw had been "an important step" and participants had "undertaken to hold regular meetings in order to ensure joint voting between the two groups".
"This is an advance that suits me very well and allows me to be optimistic for the future."
Le Pen said she hoped that eventually a single group in the European Parliament could be formed which would be the second-biggest force after the centre-right European People's Party.
She said that such an alliance was "all the more necessary now that we are faced with a German coalition which has made federalism a priority and will definitely also increase migration pressure".
The party leaders agreed to meet at least every two months at the European Parliament, while another meeting is planned in Spain in two months "to continue to move forward on strengthening and creating that big European force," Le Pen said.
One notable absentee was Matteo Salvini, leader of Italy's League, which put out a statement saying that "the time needs to be right" for the new group.
Salvini was one of the signatories of a declaration in July by 16 parties and movements announcing plans for a "grand alliance" in the European Parliament -- the prelude for Saturday's talks.
The League and Le Pen's National Rally are in the European Parliament's Identity and Democracy Group, while PiS, Vox and the Brothers of Italy party are in the European Conservatives and Reformists Group.
Orban's Fidesz left the centre-right European People's Party, the biggest group in the European Parliament, in March and is looking for a new home.
Wojciech Przybylski, editor in chief of Visegrad Insight, a policy journal focused on Central Europe, said there is a paradox in a "transnational meeting of nationalist parties." He thinks the event was organised so the party leaders can show their voters "they are not alone."
Both the Hungarian and Polish ruling parties, he noted, are “in deep trouble," with Orban’s Fidesz party forced to leave the main grouping of conservatives at the European Parliament, and Poland’s governing populists seeing a drop in popularity at home.
"This is essentially a PR stunt," Przybylski said.
Le Pen mends ties with Poland
Kaczynski’s welcome of Le Pen marks a recent change of heart for Poland’s governing conservatives. The ruling Law and Justice party had long refused to cooperate with the French presidential candidate due to her warm relations with Russian President Vladimir Putin — a turnoff in a country long dominated by Russian and Soviet rule.
"We have as much in common with Ms Le Pen as with Mr Putin," Kaczynski remarked in 2017. Two years later, he described Le Pen’s party as being among several groupings in Europe that were "obviously linked to Moscow and receive its support," citing such ties as an impediment to cooperation.
But Polish Prime Minister Mateusz Morawiecki met with Le Pen in Brussels in October and hosted her for a dinner in Warsaw on Friday evening.
In a tweet, Le Pen posted a photo of herself with Morawiecki and thanked him for his welcome. She said they share a wish for "a Europe of nations to give back to the peoples of Europe their freedom and their sovereignty.”