EU enlargement commissioner Marta Kos faces resurfaced allegations of ties to Yugoslav secret services

European Commissioner for Enlargement Marta Kos is once again confronting claims that she collaborated with the former Yugoslavia’s secret police in the 1980s, allegations that first emerged during her 2024 confirmation hearing and have now been revived through a new book and political scrutiny in the European Parliament.

While Kos has consistently denied the accusations, calling them disinformation, the timing – ahead of Slovenia’s national elections on 22 March – has amplified the debate, raising questions about potential impacts on her high-profile role in guiding EU expansion.

The issue gained fresh momentum this week when her compatriot, Slovenian MEP Romana Tomc, a vice president of the centre-right European People’s Party (EPP) – the Parliament’s largest group – presented a book by Slovenian author Igor Omerza during a parliamentary event in Strasbourg.

Tomc claimed the book contains archival documents proving Kos’s involvement with the Yugoslav State Security Administration (UDBA), the secret police under the communist regime. She has since sent a letter to the European Commission demanding an investigation, arguing that Kos was not forthcoming during her confirmation process.

“The credibility and legitimacy of the Union are at stake,” Tomc stated on social media, urging at least a “clear explanation” from Kos.

Omerza’s book, which draws on purported declassified files, alleges that Kos was registered as a collaborator under the code name “Mira” and provided information to UDBA agents while working as a journalist in the late 1980s, just before Slovenia’s independence in 1991. These claims were echoed in reports by outlets like BGNES, a Bulgarian news agency partnering with EUalive, which highlighted documents suggesting Kos’s links to the agency during a period of political turbulence in Yugoslavia.

However, the authenticity and context of these documents remain unverified by independent sources, and critics have noted that similar lists from the era include thousands of names, often without clear evidence of active collaboration.

“I was never a collaborator”

Kos, a Slovenian diplomat and former ambassador nominated by Prime Minister Robert Golob’s left-liberal Freedom Movement (affiliated with the Renew Europe group), addressed similar accusations head-on during her 2024 parliamentary hearing. When questioned by Renew MEP Ilhan Kyuchyuk about media reports alleging her involvement with the Yugoslav secret services, Kos responded: “I have read so many new things that I never knew about me. I took this seriously, even if I was sad because there were many, many lies. … I was never a collaborator or informant of the secret service of Yugoslavia. I am on that list, I don’t know how, but on that list are also three past prime ministers, three past presidents of the State, three past Members of the European Parliament. There are thousands and thousands of people on this list.”

Sources familiar with the hearing suggest Kyuchyuk’s question was strategically posed from friendly ranks to allow Kos to rebut the claims and defuse potential attacks from hostile groups, such as the right-wing Slovenian Democratic Party (SDS). At the time, Kos emphasized her commitment to integrity: “If I go through, if I will be confirmed, I tell you, integrity is so much important in my life. That’s why I wouldn’t want to see this challenged by the accusations which really, Mr Kyuchyuk, go into the direction of disinformation.”

Despite her denials, the resurfacing of the story has coincided with reports of disruptions to Kos’s schedule. She recently postponed a planned visit to Kosovo, citing political developments there, though some observers link the broader scrutiny to her ability to maintain a full agenda.

As the scandal unfolds, it risks casting a shadow over Kos’s tenure at a critical juncture for EU enlargement. The portfolio, which oversees accession talks with candidates like Ukraine, Moldova, and Western Balkan states, demands unwavering credibility and diplomatic agility amid geopolitical tensions. With calls for an investigation from influential EPP figures the situation could make Kos’s position increasingly untenable.

Analysts note that prolonged controversy might paralyze key initiatives, such as advancing membership negotiations or countering disinformation campaigns from third actors, at a time when the EU’s enlargement policy is already strained by internal divisions and external pressures.

For now, the Commission has stood by Kos, pointing to her rigorous vetting process and parliamentary approval in 2024. A spokesperson on Friday reiterated that she remains focused on her duties, including an upcoming appearance before the Parliament’s foreign affairs committee next week, where enlargement priorities will be discussed – though the allegations are likely to feature prominently.

EUalive has reached out to Kos’s cabinet for comment on the latest allegations and their potential effects on her work, but the short answer received pointed out at a response already given: “the Commission has no further comments to offer”.

Pundits who have studied the operational methods of communist-era secret services often point out that many individuals labelled as “agents” or “informers” merely signed a cooperation agreement in exchange for a specific benefit – most commonly the right to travel abroad or obtain a passport. In numerous cases, these people provided little or no meaningful information, caused no real harm to others in their circle, and therefore carry no personal sense of guilt about the episode.

The distinction, however, is important: there is a significant difference between having been registered as an informer in that limited, largely passive sense, and actively denying any such involvement whatsoever when confronted with evidence.

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Caption: European Commissioner for Enlargement, Marta Kos speaks during a debate on ‘EU enlargement strategy’ at the European Parliament in Strasbourg, France, 10 March 2026. The current plenary session runs from 9 until 12 March 2026. EPA/RONALD WITTEK