A helicopter crashed in Tijuca National Park in Rio de Janeiro, killing three Colombian tourists and the pilot, Agence France-Presse reported.
The aircraft went down inside the park, a large protected forest within the city limits that includes Corcovado mountain and the Christ the Redeemer statue. Sightseeing flights over the area are a common tourist activity.
Authorities have not released the identities of those killed or a preliminary cause.
Tijuca National Park covers roughly 3,900 hectares of Atlantic forest and is among the largest urban forests in the world. Its steep terrain and frequent low cloud can complicate low-altitude flying.
Brazilian aviation authorities typically open an investigation into civil aircraft accidents through the Center for Investigation and Prevention of Aeronautical Accidents, which issues preliminary findings within 30 days.