National Force officers shot in Rio.

247, with Reuters Three members of the National Security Force (FNS) were injured on Wednesday by gunfire from inside a favela near Rio de Janeiro's international airport after they took a wrong turn and entered an access road to the site, a security source said.

The incident occurred at one of the entrances to the Vila do João favela, which is located on the edge of the Linha Amarela highway, the road that leads from the airport to Barra da Tijuca, the neighborhood where the Athletes' Village and the Olympic Park are located, the heart of the Rio Olympic Games.

The National Force vehicle, which was sent to Rio as part of the Olympic security plan, was on routine patrol and took the wrong turn, ending up at the entrance to the favela, where it was met with gunfire, according to the source.

Shortly before the Olympic Games, National Force agents who were already in the city for the event exchanged gunfire with suspects while traveling on Avenida Brasil, one of the city's main expressways, and the police vehicle was hit in the rearview mirror, but no one was injured.

Security has been one of the biggest problems faced by the Games organizers. On Tuesday, an Olympic bus carrying journalists was hit by stones, according to authorities, during its journey from Deodoro to the Olympic Park, and two stray bullets have already landed in the Games' equestrian center.

(Reporting by Rodrigo Viga Gaier)