Croatian President Kolinda Grabar-Kitarovic visited on Friday an Air Force base near Zagreb and expressed her concern over the condition of MiG-21 fighters bought from Ukraine, the presidential administration said in a statement.

“After a conversation with pilots and familiarization with the situation the president and commander-in-chief remains concerned over the condition of material resources, particularly MiG-21 jets. She pointed out the importance of combat readiness of the Croatian Air Force and reliability of jets as a basis for implementation of the set tasks,” the statement said.

The president called for modernization of material resources and purchasing new aircraft. She also thanked pilots for their courage while fulfilling tasks on defending Croatian territory and airspace.

The scandal in Croatian Air Force erupted in 2015 when only three out of seven MiG-21 fighters repaired in Ukraine turned out to be serviceable while other four planes were non-serviceable due to their technical condition. Under the 2013 contract with the Ukraine’s Ukrspecexport state company Croatia paid $14.5 million.