Washington DC - President Donald Trump made a last-minute attempt to interfere in Hungary's bitter election campaign in favor of his far-right ally Viktor Orban on Friday.

Trump vowed to bring US "Economic Might" to Hungary if Orban's party secures a victory over his Peter Magyar in Sunday's election.

Orban, who has run Hungary for 16 years and is close to Trump and Russia's President Vladimir Putin, faces an unprecedented challenge with opinion polls putting Magyar's conservative Tisza party well ahead.

"We are excited to invest in the future prosperity that will be generated by Orban's continued leadership," Trump said on social media.

Trump's administration has engaged in blatant promotion of hard-right forces in Europe – casting migration and "woke" values as a "civilizational" threat to the continent.

Vice President JD Vance visited the country this week to underline support for Orban.

Trump had already hailed Orban as a "truly strong and powerful leader".

"Hungary: GET OUT AND VOTE FOR VIKTOR ORBAN... I AM WITH HIM ALL THE WAY!" he posted on his Truth Social platform.

During Orban's tenure, his ruling coalition has used its two-thirds majority in parliament to tilt the European country's electoral system in his favor, leverage state resources to campaign, and facilitate the takeover of media organizations by his allies.