Hungarian Prime Minister Viktor Orban has declared victory in the country's election.

• In Budapest, Hungary, Viktor Orban, who is known for his close ties with Russia, has been in power for 12 years.
• Since the fall of communism in 1989, he has been the country's longest-serving leader and has consistently been a source of tension for the European Union.
• The close relationship between Orban and Putin has been a significant obstacle for Fidesz party during the electoral campaign.

On Sunday, Hungary's nationalist Prime Minister Viktor Orban announced his party's victory in the nationwide election, with preliminary results indicating a substantial lead.

Hungarian Prime Minister Viktor Orban is poised to secure a fourth term in office, with preliminary results indicating that his party will control 135 seats of the 199-seat Parliament, comfortably ahead of the opposition alliance United for Hungary, which is expected to gain 57 seats after 80% of the votes have been counted.

Despite predictions of a closer election, Fidesz maintained a 5-6 percentage point advantage in the polls prior to Sunday's vote.

In Budapest, Orban, who is viewed as the most pro-Kremlin leader among the 27 nations of the European Union, has been in power for 12 years. He is the country's longest-serving leader since the fall of communism in 1989 and has consistently been a source of tension for the EU.

Orban declared a massive victory after the vote on Sunday night, which can be seen from the moon and even from Brussels, as admitted by opposition leader Peter Marki-Zay after his speech.

Kremlin links

The close relationship between 58-year-old Orban and Russian President Putin has been a major challenge for the electoral campaign of his ruling Fidesz party.

Hungary has significantly increased its imports of Russian natural gas and oil over the past decade, with Russia now accounting for nearly 85% of Hungary's gas imports and 64% of its oil imports.

Hungary was the first EU country to purchase a Russian-made Covid-19 vaccine, despite it not being authorized by European regulators.

Despite his ties to Putin, Orban has remained loyal to the EU and has sought to downplay his relationship with Russia in the wake of its invasion of Ukraine. His messaging has been focused on keeping Hungary out of the conflict.

Hungary's government has announced its support for Ukraine's membership application to the EU and will welcome Ukrainian refugees, in addition to imposing sanctions on Russian oligarchs and the Russian economy with the other EU member states.

Hungary is a NATO member and open to hosting troops from the military alliance on its territory, but it has rejected energy sanctions on Moscow and banned the direct transit of lethal weapons to Ukraine via Hungary.

Influence over courts

Budapest has frequently been at odds with Brussels since joining the EU in 2004, with the former communist state often facing criticism for attempting to exert influence over courts, the media, and other independent institutions.

Fidesz, the party of Hungarian Prime Minister Viktor Orban, maintains tight control over state media and has campaigned on an anti-immigration and protectionist platform. In response to the 2015 European migration crisis, Hungary constructed a fence along its southern border.

Teneo's Central and Eastern Europe advisor, Andrius Tursa, predicts that the winner of Sunday's election will face challenges such as slowing economic growth, high inflation, and a large influx of refugees from Ukraine.

Last week, in a research note, Fidesz highlighted the economic and humanitarian challenges posed by the war in Ukraine to urge the European Commission to release EUR 7.2bn grants from the EU Recovery and Resilience Facility, which is part of the EU's post-pandemic recovery fund.

The EC may be hesitant to use the rule of law mechanism against Hungary (and Poland) until the war in Ukraine ends, giving more time for negotiations. This mechanism is a new tool that allows the EU to withhold or cut funding to member states that violate the rule of law.

—CNBC’s Silvia Amaro and Sam Meredith contributed to this article.