The Brazilian military discovered an improvised bomb in a parking garage bathroom at the shrine of Our Lady of Aparecida July 22, which Pope Francis is due to visit on Wednesday, July 24.

"It was a homemade device with little potential to cause fatalities," according to a statement from the Brazilian Air Force. "It is worth pointing out that such episodes formed part of our security forces' training in Aparecida and at no point were civilians' lives in danger."

The bomb has already been destroyed. It was discovered around 11:30 am in Rio, during the completion of simulated exercises by security forces, according to Brazil's Grupo Estado.

Pope Francis landed in Rio de Janeiro this afternoon and was driven through the city in a car with its windows down, as tens of thousands of faithful swarmed around the Roman Pontiff.

He was transferred to an open-air popemobile, and later addressed representatives of the Brazilian government and met in private with the nation's president, Dilma Rousseff.

During his address, Pope Francis urged World Youth Day pilgrims "to show consideration towards each other" and "the sympathy needed to establish friendly dialogue."

He added that he had come to Brazil in Jesus' name, "to feed the flame of fraternal love that burns in every heart."

Pope Francis is due to arrive at the Aparecida shrine the morning of July 24, venerating the image of Brazil's patroness. He will say Mass at the basilica at 10:30 a.m., and then meet with local bishops and seminarians.

Aparecida will have around 5,000 members of various security forces on duty when Pope Francis visits to the city.