US F‑35s were detected by Russian S‑400 missile system after the Iranian attack
https://bulgarianmilitary.com/2020/01/20/us-f-35s-were-detected-by-russian-s-400-missile-system-after-the-iranian-attack/
GlobalDefence.net -Streitkräfte der Welt
Sicherheitspolitik weltweit
https://bulgarianmilitary.com/2020/01/20/us-f-35s-were-detected-by-russian-s-400-missile-system-after-the-iranian-attack/