KIEV, May 14. /ITAR-TASS/. The Ukrainian State Aviation Service ordered national air carriers on Wednesday to suspend both regular and charter flights to republics located in Russia’s North Caucasus.

The document, which was signed by Ukrainian State Aviation Service’s head Denis Antonyuk and posted on the service’s website, bans the flights of national air carriers to the following Russia’s North Caucasus republics: Chechnya, Dagestan, Ingushetia, Kabardino-Balkaria, Karachai-Cherkessia and North Ossetia.

According to the document flights to the republics mentioned above are permitted only after a special permission issued by Ukraine’s Department of Aviation Security.

The Ukrainian aviation authorities have also banned all flights to former Georgian republics of South Ossetia and Abkhazia.

The move is the most recent in a string of events concerning air space spat between Russia and Ukraine.

Earlier in the year Ukraine closed its airspace for flights to and from Crimea since the peninsula’s merger with Russia in March. The airspace over Crimea is now controlled by Russia and its aviation authorities.

Starting from May 2, the Ukrainian aviation authorities unilaterally banned Russian air companies from making flights to the south-eastern Ukrainian cities of Donetsk and Kharkiv.

After Crimea’s accession to Russia on March 18 following a referendum two days before, protests against the new Ukrainian leaders erupted in Ukraine’s Russian-speaking south-eastern territories, with demonstrators seizing some government buildings and demanding federalization.

Kiev has been conducting a punitive operation against pro-federalization activists.

The eastern Ukrainian Donetsk and Luhansk regions held referendums on May 11, in which most voters supported independence from Ukraine.