Hungarian Prime Minister Viktor Orban speaks at the Kossuth Lajos Square in Budapest, Hungary, Sunday. (Reuters-Yonhap)
Hungarian Prime Minister Viktor Orban speaks at the Kossuth Lajos Square in Budapest, Hungary, Sunday. (Reuters-Yonhap)

BUDAPEST, Hungary (AFP) -- Huge crowds joined rival marches staged by Hungarian premier Viktor Orban and his main opponent Peter Magyar in Budapest Sunday, as both push allegations of foreign interference just four weeks before tightly fought elections.

Orban -- who faces an unprecedented challenge to his 16-year rule -- has sought to portray the opposition leader as a "puppet" of Brussels and Kyiv, while Magyar has accused the Moscow-friendly premier of seeking the Kremlin's help to stay in power ahead of the April 12 elections.

The nationalist leader in his speech on Sunday pledged that his government "will preserve Hungary as an island of safety and calmness in such a chaotic world," also urging Ukraine to stop "attacking" the central European country.

Orban has accused Kyiv of blocking a key pipeline transporting Russian oil through Ukraine to Hungary.

Tens of thousands of people attended both rallies, according to Agence France-Presse journalists on site.

Opposition supporters marched behind horsemen dressed as hussars -- Hungary's historic light cavalry formation.

Accusations against Magyar's party are "all just empty words," said Noemi Kiss, a 28-year-old communication manager.

"They're trying to divert attention away from the scandalous state of public affairs," she told AFP.

Magyar, who is due to speak later Sunday, has previously denied the government's accusations that his party received funds from Ukraine.

In turn, he has accused Orban of seeking the Kremlin's help to stay in power following reports by regional investigative outlet VSquare and the Financial Times of a covert Russian social media campaign to boost Orban and weaken the opposition.

Hungarians from around the country traveled to Orban's "peace march" on the country's national day, many using buses rented by a group close to Orban's Fidesz party.

"There is unrest all over the world, and here in our little country we want to preserve peace, calm and security. And Viktor Orban ensures that for us," said Sandorne Pista, 60, who came from the southern university town of Pecs.

Since Orban's return to power in 2010, gatherings in support of the ruling Fidesz party, dubbed "peace marches," have routinely been held, especially before elections as a show of force.

"We will not be a Ukrainian colony," read one of the banners carried in front of the crowd, which later chanted "Viktor, Viktor" in front of the parliament as the Hungarian premier took the stage.

"Give us our oil, then roll your trucks over to the cash register in Brussels to collect money from the West, since they can't say no," Orban said in reference to the ongoing oil dispute with Kiyv.

Orban's party has been trailing in polls since last year, and he has recently centered his campaign on attacking Ukrainian President Volodymyr Zelenskyy.

Tensions between Zelenskyy and Orban reached new heights, when Zelensky appeared to issue a direct threat against Orban and Hungary detained and then expelled a group of Ukrainian bank employees.

Orban told supporters that either he or the Ukrainian leader will form Hungary's next government.

Zelenskyy in a fresh statement Sunday accused the government of spreading "anti-Ukrainian sentiment."

"We are ready to work amicably, provided this person is not an ally of (Russian President Vladimir) Putin, specifically the aggressor state," he said.

Billboards casting Zelenskyy in a negative light have sprung up in recent weeks across the country, using images of the Ukrainian leader next to Magyar.

"Orban is doing everything he can to rev up the war psychosis that brought him a fourth supermajority in 2022" after Russia invaded Ukraine, Robert Laszlo, an election specialist at Political Capital think-tank, told AFP.

"After 16 years in power, Orban does not have a good answer to Magyar's chief message about public services failing due to widespread corruption," Laszlo added.

Last month, Orban ordered reinforced security around Hungary's key energy facilities, alleging that Ukraine was preparing "operations" against such sites.

This prompted renewed accusations from Magyar that he could be preparing for a "false flag operation."