Marine Le Pen, leader of France's National Front (FN), and Dutch far-right leader Geert Wilders saluted the advance of Germany's hard right AfD after the nationalists on Sunday became the third-largest party in parliament.
"Bravo to our AfD allies for this historic score," tweeted Le Pen, defeated by Emmanuel Macron in the French presidential election run-off four months ago.
Le Pen hailed the AfD after its breakthrough score of 13 percent, enough for close on 90 seats, saying the party was a "new symbol of (the) reawakening of European peoples."
Wilders, head of the Dutch Party for Freedom (PVV), also tweeted his congratulations.
"I congratulate @FraukePetry (joint-chair of the AfD)) and @AfD," said Wilders, publishing a picture of himself alongside both Le Pen and Petry.
"The PVV is number two in the Netherlands, the FN is number two in France, the (far right) FPOe is second in Austria, AfD is third in Germany. The message is clear. We are not Islamic nations," wrote Wilders, whose party captured 20 seats in a March election.
One AfD (Alternative for Germany) Euro MP already sits alongside five FN lawmakers and four PVV colleagues in the European Parliament.