The Argentine police reinforced security Thursday in the mountain resort of Bariloche, where a summit of the Union of South American Nations (Unasur) is to be held on Friday.
Some 3,000 policemen from the National Police (GNA) and the Federal Police (PFA) will guard the summit venue, a hotel in Bariloche, 1,627 km southwest of Buenos Aires.
Bariloche's airspace is to be closed from 12:00 a.m. local time(1500 GMT), but commercial flights will continue without restrictions till 6:00 p.m. local time (2100 GMT).
After that time only planes carrying the attending presidents will be allowed to fly over the area, and all the other passengers will be evacuated from the airport.
From 12:00 a.m. local time (1500 GMT) the city will not provide any service of leasing cars, while private vehicles will be moved to a military quarters to avoid being targeted by criminals.
Since early Thursday morning, military fighters supported by ground mobile radars have been patrolling the local airspace to "detect possible intruders" or "eventual threats."
According to the Argentine authorities, the Joint Operational Commander of the Armed Forces had created the Aerospace Defense Sector of Bariloche (SEDABAR) for the upcoming summit.
The SEDABAR is responsible for patrolling and controlling the air traffic at the San Carlos de Bariloche airport, in order to protect the presidential airplanes flying to the city.
The SEDABAR includes the deployment of A4-AR Fightinghawks and IA-58 Pucura planes from the Air Force as well as UH-1H helicopters from the Army.