Tehran, Sept. 28 -- Iran's Civil Aviation Organization has filed a formal protest with the UN aviation watchdog, the International Civil Aviation Organization (ICAO), against restrictions imposed by the United States on Iranian aviation, as Tehran pursues diplomatic and legal measures to restore suspended flight routes.

Iranian Civil Aviation Organization chief Abuzar Shiroudi on Monday told IRNA that the Iranian organisation, in coordination with the Foreign Ministry, was using all available legal avenues to remove barriers and resume flight routes that had previously been in operation.

Speaking to IRNA, Shiroudi said Iran's formal protest had been submitted to ICAO along with supporting documents detailing disruptions to flights cause...