Brazilian journalist Renato Machado Goncalves was shot and killed outside his home in this metropolis, the radio station he partly owned reported Wednesday.

Witnesses cited by the Radio Barra FM station and other media outlets said the reporter was attacked by two men who had apparently been waiting for him outside his home in the Rio suburb of Sao Joao da Barra and fled in a motorcycle afterward.

Goncalves, who was shot four times, received emergency medical treatment but died while being rushed to a hospital.

Police said they have not yet identified a motive for the shooting but have launched an investigation.

Reporters Without Borders, for its part, urged authorities Wednesday to step up security for journalists in the wake of the attack.

The Paris-based press watchdog, known by the French initials RSF, noted that "the recent flight abroad of well-known (Brazilian) journalists such as Andre Caramante - who has since returned - and Mauri Konig underlines the urgent need for better protection."

In its 2012 annual report, RSF ranked Brazil as one of the most dangerous countries for journalists to carry out their work, noting that five media members were killed last year for reasons related to their profession.

The group also has warned in press releases about the deterioration of press freedom in that South American nation. EFE