MADRID (Reuters) - Spanish far-right party Vox held a mass rally in Madrid on Sunday ahead of the European election, touting the support of international allies including Argentinian President Javier Milei, the prime ministers of Italy and Hungary and rightwing leaders from France and Portugal.

Nearly 11,000 supporters - according to Vox - packed a former bullring waving hundreds of Spanish flags, as well as some of Argentina, Cuba, Venezuela and Israel.

They cheered speakers ranging from French presidential candidate Marine Le Pen to the leader of Portugal's Chega, Andre Ventura, and jeered at every mention of Spanish Prime Minister Pedro Sanchez, the United Nations' 2030 Agenda, feminism or socialism.

Milei earned a standing ovation with a speech in which he excoriated "lefties" and defended free market capitalism. He also thanked Vox leader Santiago Abascal for his early friendship, "when I was lonelier than Adam on Mother's Day".

The presence of foreign dignitaries prompted tight security, days after the shooting of Slovakia's Robert Fico.

Italian Prime Minister Giorgia Meloni, who appeared via a live video-link, won applause for her speech in Spanish in which she attacked irregular migration and surrogate pregnancies.

Hungary's Viktor Orban and former Polish premier Mateusz Morawiecki extolled what they called Europe's Christian values in pre-recorded videos.

Chile's presidential runner-up Jose Antonio Kast and Israel's Diaspora Affairs Minister Amichai Chakli received a more muted reception.

But enthusiasm was high for former U.S. President Donald Trump, represented in Madrid by the vice president of the conservative Heritage Foundation and former White House staffers Matt and Mercedes Schlapp.

The event ended with Spain's national anthem while insults were hurled at the reporters present.

Like its partners in the European Parliament's ECR group, Vox hopes to ride a populist wave in the June 9 election to increase its current representation of four MEPs.

A poll by Cluster 17 released on Friday showed Vox garnering 8.8% of the vote and six seats.

Vox's best showing in a general election came in 2019, when it won 52 seats in the 350-seat lower house boosted by Catalonia's failed bid for independence. Its support has since waned but it remains the third-largest party in parliament with 33 seats.

(Reporting by David Latona; Editing by Giles Elgood)

By David Latona