Military police in Brazil on Tuesday detained three men for flying a drone over Brazil's CONMEBOL World Cup qualifying training session in CT do Caju in Curitiba, home to Brazil league first-division team, Atlético Paranaense.

The three men, from Ecuador, Venezuela and Brazil, respectively, were detained and questioned on Tuesday.

Curitiba MPs said that espionage has not been ruled out, although no arrests have been made.

"Initially [the accusation against the suspects] is of exposing others to a health risk or endangerment, but we will investigate whether they were not using this drone to illegally capture images to make some kind of sale or something like that," Lt. Everton Taborda of the Curitiba MPs told ESPN Brasil.

Brazil host Ecuador on Friday in Curitiba.

Taborda said the police have not yet been able to access the drone images or what was archived on the seized computer.

He said no criminal charges will be filed against the owner of the drone unless Athletico-PR decides to file a complaint.