The Brazilian Air Force announced Tuesday that air traffic will be restricted over Rio De Janeiro during the upcoming UN Conference on Sustainable Development (Rio+20).

The no-fly zone will be in place until the day after the June 20-22 conference, with restrictions being phased in as of now, according to the Air Force.

Airspace directly above the conference site, the Riocentro convention center, and within a one-km radius has already been restricted to all flights, except for medical and military aircraft previously authorized by the Airspace Defense Command.

Starting on June 16, the no-fly zone will be expanded to four kilometers around Riocentro, with the exception of previously scheduled flights landing or taking off from the city's Jacarepagua airport.

Finally, during the three-day conference, the restricted area will be expanded to 14 kilometers, and the Jacarepagua airport will be reserved for the exclusive use of military aircraft.

The Brazilian authorities estimate that some 30,000 representatives from around the world will attend the UN conference and its sideline events.