US Vice-President JD Vance is due in Hungary to back veteran Prime Minister Viktor Orban, a key European ally of the Trump administration, during a challenging parliamentary election.

Vance is expected to address an election rally with Orban in a football stadium in Budapest on Tuesday afternoon.

Recently, US President Donald Trump expressed his complete and total support for Orban in a video message during the Hungarian Conservative Political Action Conference (CPAC).

The election on April 12 is anticipated to be Orban's toughest challenge in a political career spanning nearly 40 years.

He faces Peter Magyar, a former ally turned adversary, who leads in the polls with his centre-right Tisza party, indicating discontent among voters. Only pro-government polls suggest a narrow Fidesz advantage.

The political alliance between Orban and Trump dates back to 2016 when Orban was the first EU leader to endorse Trump's presidential campaign.

This relationship has deepened, especially as Orban sought exemptions from US sanctions on Russian energy companies.

Contrary to EU pressures, Hungary has continued to rely on Russian fossil fuels, sourcing oil through pipelines while promising to increase imports of US liquefied natural gas and invest in US nuclear technologies.

As conflict disrupts its Russian oil supply, Hungary has begun releasing fuel reserves and looking for alternatives.

Compounding this, a potential attack on the TurkStream pipeline was discovered, raising tensions further. Critics allege that Orban may be leveraging national security concerns to bolster his campaign.

Recent leaks of phone conversations involving Hungary's foreign minister and Russian officials have also raised eyebrows, indicating potential conflicts of interest.

With elections on the horizon and mounting controversies, Orban hopes that Vance's visit helps sway undecided voters in his favor, positioning him as a robust leader amidst turbulence.