Nationalist parties from across Europe held a rally on Saturday, led by Italian Deputy Prime Minister Matteo Salvini, promising to reshape the continent following next week's EU parliamentary election.

Thousands of flag-waving supporters of Salvini's League party packed a rain-soaked central Milan square to see far-right and anti-immigrant leaders from 11 European Union countries present a common front in their battle to pull back power from Brussels.

Hundreds of opponents gathered on the sidelines, their boos, jeers and whistles sometimes drowning out the speakers. "Fascists leave Milan," they chanted as Salvini took the stage.

"There are no extremists, racists or fascists in this square," Salvini said. "Here you won't find the far-right, but the politics of good sense. The extremists are those who have governed Europe for the past 20 years."

 Salvini is confident his newly forged alliance will win a record number of seats at the May 23-26 election, giving it a strong say in how Europe is run over the coming five years.

However, the gathering in front of Milan's Gothic cathedral was overshadowed by a scandal engulfing one of Salvini's most prominent allies, Austria's Freedom Party, whose leader quit on Saturday as government vice-chancellor after he was videoed offering state contracts in exchange for political support.

While the beleaguered Freedom Party had to skip Saturday's event, parties from 11 countries did show up, including France's National Rally (RN), Germany's Alternative for Germany (AfD) and the Dutch anti-Islam Freedom Party (PVV).

"This is a historic moment," said RN leader Marine Le Pen, telling the crowd that Europe had to be protected from uncontrolled immigration that had brought millions of refugees and asylum seekers to the continent since 2014.

"We say no to this immigration which has submerged our nations, putting our people at risk," she said, playing up an issue that has helped fuel support for nationalist groups.

Recent polls suggest Salvini's alliance will end up with the fourth largest bloc of seats in the next EU parliament, but Le Pen said a number of other parties might eventually join it, including Hungarian Prime Minister Viktor Orban's Fidesz party, which is currently anchored to Europe's mainstream right.

Orban has publicly supported Salvini and promised cooperation after the vote, but he has so far refused to join any alliance with Le Pen, underscoring the divisions which have constantly plagued the nationalist camp.

The parties in the group share the broad goals of returning power to EU member states, curbing immigration and preventing the spread of Islam in Europe.

But they often have different social and economic policies, including budgetary discipline, meaning they might struggle to put forward a coherent policy agenda.

(Cover: Italy's Deputy Prime Minister Matteo Salvini poses for a selfie with supporters during a major rally of European nationalist and far-right parties ahead of EU parliamentary elections in Milan, Italy May 18, 2019. /Reuters Photo)