Slovakia launches inquiry into transfer of classified S-300 data to Ukraine
Photo: S-300 air defense system in service with Ukraine (Mil.in.ua)
In Slovakia, police are investigating possible espionage linked to the transfer of classified documentation related to the S-300 air defense missile system to Ukraine in 2022, Aktuality reports.
According to law enforcement officials, the case concerns the handover of top-secret technical materials to a Ukrainian military attaché on April 15, 2022.
Investigators say the transfer may have violated an intergovernmental agreement between Slovakia and Russia on the protection of classified information.
The Bratislava Prosecutor’s Office announced the investigation. It has been ongoing since April last year. Authorities are currently collecting documents and questioning witnesses, and no deadline for completing the probe has been set. According to prosecutors, the documentation was transferred to Ukraine after the air defense system itself had already been delivered.
Former Slovak Defense Minister Jaroslav Naď described the investigation as absurd, stressing that the transfer of the S-300 system to Ukraine took place at the start of Russia’s full-scale invasion by government decision, and that all necessary documentation is a standard part of such systems.
Slovak law enforcement authorities had previously examined the fact of transfer of the S-300 system to Ukraine, including on suspicion of sabotage, but all related criminal complaints were dismissed.
Overall, the regional prosecutor’s office opened four criminal cases, three of which have already been closed. A separate investigation into the transfer of ammunition to Ukraine is still ongoing and is being overseen by the European Public Prosecutor’s Office.
What is known about the S-300
The S-300 is a Soviet-era long-range surface-to-air missile system designed to engage aircraft, cruise missiles and ballistic missiles.
Developed in the 1970s, it became a cornerstone of air defense for the Soviet Union and its allied countries.
Depending on the variant, the S-300 can engage targets at ranges of up to 150 kilometers and at high altitudes.
Ukraine uses these systems to protect its airspace from Russian missiles and aircraft.
Slovakia investigated transfers of MiG-29s and air defense systems
After coming to power in 2023, Slovakia’s government under Prime Minister Robert Fico halted state military aid to Ukraine, shifted to pro-Russian rhetoric, blocked Ukraine’s NATO membership, and threatened to veto EU financial assistance.
Bratislava also withdrew from participation in credit guarantees and from sending troops.
Fico’s government further accused the country’s previous administration of treason and crimes for various donations to Ukraine. In November 2024, an investigation was launched into discrepancies in data related to those donations.
In addition, Fico called on police to investigate the previous government over the transfer of MiG-29 fighter jets and air defense systems to Ukraine.
In November 2025, law enforcement authorities reported that they had found no evidence of criminal wrongdoing in the previous government’s decisions to transfer Soviet-era MiG-29 fighter jets and the KUB air defense system to Ukraine. The case was closed.
