Hungarian Prime Minister Viktor Orban on Monday said he had ordered an investigation into what he has referred to as the "wiretapping" of Foreign Minister Peter Szijjarto. 

"The wiretapping of a government member is a serious attack on Hungary. I have instructed the Minister of Justice to immediately investigate the information," Orban wrote on Facebook. 

This comes after a weekend media report in the Washington Post, dismissed by Szijjarto himself as "fake news" and "senseless conspiracy theories," accusing the Hungarian foreign minister of regularly passing on sensitive information about European Union negotiations to Russia.

The report made no mention of "wiretapping," instead accusing Szijjarto of deliberately briefing his Russian counterpart Sergey Lavrov. 

Europe, Germany voice concern at allegations

The Washington Post report cited unnamed serving or former EU security officials as saying that Szijjarto regularly called Russia's Lavrov during breaks in EU meetings to give "direct reports on what was discussed" and suggest possible courses of action. 

The European Commission on Monday stopped short of treating the allegations as corroborated but nevertheless demanded an investigation and explanation.

"[A] relationship of trust between member states, and between them and the institution, is fundamental for the work of the EU," spokeswoman Anitta Hipper said, calling the allegations deeply concerning. "We expect the Hungarian government to provide clarifications." 

A spokesman for the German Foreign Ministry also stopped short of directly implicating Szijjarto.

"The allegations that are being raised here are very serious," he said. "Negotiations between EU foreign ministers are confidential and rooted in the founding principles of the Union. We will not tolerate a violation of these principles."

EU and NATO member Hungary at odds with allies on Ukraine aid, Russian oil

The report comes near the climax of a close-fought election campaign in Hungary, where longstanding Prime Minister Orban faces probably his sternest electoral test ever against a breakaway who was once part of his own Fidesz party, Peter Magyar. 

It also comes as Orban seeks to block or delay an EU loan of €90 billion (roughly $105 billion) to the government in Ukraine, demanding that oil deliveries through the Druzhba pipeline are restarted first. 

European leaders have accused Orban of holding Ukraine to ransom for electioneering purposes, while Orban has in turn accused the EU of seeking to meddle in Hungary's elections as he seeks a fifth term.

Hungary, a member of both the EU and NATO, has maintained arguably the closest ties to Moscow of any Alliance or Union member amid Russia's full-scale invasion of Ukraine. 

Polish Prime Minister Donald Tusk said the Washington Post report "shouldn't come as a surprise to anyone." 

"We've had our suspicions about that for a long time. That's one reason why I take the floor only when strictly necessary and say just as much as necessary," Tusk, also the former head of the European Council, said.

Edited by: Dmytro Hubenko