Slovakia’s Ministry of Defence is to pursue a lawsuit against the previous cabinet of Prime Minister Eduard Heger and Defence Minister Jaroslav Nad over last year’s supply of 13 MiG-29 fighter jets to Ukraine.

“A criminal complaint directed towards the cabinet of Eduard Heger and the ex-minister Jaroslav Nad will be filed during the course of Friday,” state secretary at the Ministry of Defence Igor Melicher said at a press conference on June 21.

The ministry is headed by Robert Kalinak, one of the closest collaborators of populist Prime Minister Robert Fico at the Leftist Smer party. Smer returned to power last October and immediately axed the state military support of Ukraine, describing it as an election promise after it campaigned aggressively against military support. Fico’s cabinet backs nevertheless commercial military support of Ukraine.

Slovakia, followed shortly after by Poland, was the first Nato country to donate fighter jets to Ukraine, and it had done so while Heger’s second cabinet was without parliamentary backing.

Melicher described Heger’s cabinet’s decision as conflicting with the constitution and with contractual obligations on military equipment. He also said that “skies were left unprotected and citizens remained at risk”.

Under the previous cabinet, Slovakia was one of the most active countries in delivering heavy weapons to Ukraine after it delivered an anti-aircraft missile system S300, and a Slovak artillery system Zuzana. Together with 13 MiG-29 fighter jets, Slovakia also supplied the KUB missile system.

Slovakia has largely emptied its Soviet-era military stockpiles in favour of Ukraine and was reimbursed with €850mn in compensation from the US and EU for the MiG-29 deliveries. Slovakia is also poised to receive 12 AH-1Z Viper US-made fighter helicopters at a reduced price.

The country’s MiG-29 fleet was grounded in 2022 and Czech and Polish air forces have been patrolling Slovak skies. Slovakia ordered US-made F-16s in 2020. These are supposed to arrive this year and Kalinak hinted in May that the country could purchase more US fighter jets.