Brazil's Defense Minister Raul Jungmann (R) meets marines taking part in a simulated hostage situation during a security exercise ahead of the 2016 Rio Olympics in Rio de Janeiro, Brazil, July 21, 2016. [Photo/Agencies]

On Thursday, the government held a press conference where it announced that, in order to control and supervise transport, over 21,000 soldiers from the Brazilian army will patrol highways, train stations, the Rio port and the city's airports.

During the Olympic Games, an elite military unit will also be responsible for security at competition sites, while Rio's military police will focus on public security on the streets.

On July 24, when the Olympic Village opens, restrictions will begin on the airspace around Rio, with the air force having 80 planes and 15,000 personnel to ensure air safety.

At the conference, Defense Minister Raul Jungmann said that no terrorism suspect will be able to enter Brazil without being spotted and monitored.

"Brazil is a peaceful country but it is not a defenseless country. We know how to defend ourselves and counter-attack. If something happens without our knowledge, we will be untiring and implacable in pursuing and punishing those responsible," emphasized the minister.

Jungmann also added that representatives "from intelligence agencies and systems of 106 countries" would also be on the ground to help security efforts.

New security norms also entered into force on July 18, with increased checks at airports, including random searches of passengers and luggage.

Last week, a simulation of a terrorist attack on a train in the Deodoro station united for the first time all the Brazilian forces operating as part of the Olympic security plan.

The exercise, involving around 1,000 police, soldiers, security agents and extras, simulated the explosion of a "dirty bomb" by two terrorists in a train compartment.

The exercise had been planned by around 20 institutions for six months, to simulate conditions as real as those that might occur.

Such simulations will continue in the coming days, until the first athletes arrive on July 24.