Magyar, Hungary’s main opposition figure and front-runner in the parliamentary election campaign, demanded scrutiny of allegations that Hungary has shared sensitive European Union discussions with Russia—an accusation he said could amount to “treason.” In a social media post on Monday, Péter Magyar reacted to a Washington Post report, arguing that if the claims were confirmed they would carry a potential life sentence and should be investigated by a future Tisza government, according to the Associated Press account.

The report in question, the Washington Post said, relied on current and former European security officials and described a long-running channel between Budapest and Moscow. It alleged Hungary’s government has for years provided Russia access to details from EU Council meetings, with the most recent accusations focused on Foreign Minister Péter Szijjártó’s contacts with Sergei Lavrov.

Magyar said Szijjártó “appears to be colluding with Russia, thereby betraying Hungarian and European interests,” and he called for an immediate probe if the information was verified. The Tisza party, which Magyar leads, is ahead in the polls three weeks before the parliamentary elections, and the race is widely framed as an attempt to unseat Viktor Orbán’s nationalist Fidesz party, which has been in power since 2010.

The Washington Post report alleged that during breaks at EU meetings—including the summit of the bloc’s 27 leaders last Thursday—Szijjártó made regular phone calls to provide Lavrov with “live reports on what’s been discussed” and possible solutions, according to one European security official cited by the paper. The official also said that, through such calls, “every single EU meeting for years has basically had Moscow behind the table.”

The AP account also reported that Szijjártó has made 16 official visits to Moscow since Russia’s full-scale invasion of Ukraine in 2022, most recently on March 4 when he met with President Vladimir Putin. Szijjártó’s office did not immediately respond to a request for comment.

Orbán, who leads the governing party, said he had instructed his government to launch a probe into allegations of “wiretapping” of Szijjártó that he said were evidenced in the Washington Post report. In a separate social media post, Orbán said: “The wiretapping of a government member is a serious attack on Hungary. I have instructed the Minister of Justice to immediately investigate the information regarding the wiretapping of Péter Szijjártó.”

The European Commission also weighed in, saying it was seeking information from Hungary. “A relationship of trust between member states and between the institution is fundamental for the work of the EU,” a commission spokesperson, Anitta Hipper, said on Monday. “We expect the Hungarian government to provide clarifications.”

The dispute adds to strain inside the European Union that has grown since Russia’s invasion of Ukraine. Relations between Hungary and other EU member states took a sharp turn earlier this month after Orbán backtracked on an agreement to provide Kyiv with a 90-billion euro ($104 billion) loan, the AP account said.

Poland’s Prime Minister Donald Tusk, who has often clashed with Orbán, also addressed the allegations in a social media post Sunday. Tusk wrote that the news that “Orbán’s people inform Moscow about EU Council meetings in every detail shouldn’t come as a surprise,” and he said he had long suspected the practice.