KIEV, December 15. /TASS/. Three major airports - Kharkiv, Dnipropetrovsk and Zaporizhia - have been closed indefinitely, Ukraine’s State Air Traffic Service said on its website on Monday.

“Flights to the airports of Dnipropetrovsk, Kharkiv and Zaporizhia are banned for security reasons,” the air service said.

Earlier, the service’s chief, Denis Antonyuk, said the airports would be closed till Tuesday morning.

This is not the first time the Ukrainian state aviation service closes Ukrainian airports. Air links with the Ukrainian eastern city of Donetsk have been disrupted since May. Flights between Kharkiv and Moscow were banned last May, too, and between Dnipropetrovsk and Moscow, in December.