France, Sept. 3 -- Kaka, who worked for many years as an RFI correspondent in Niger and now directs private broadcaster Radio Television Saraounia, left his office in Niamey on Monday evening and never arrived home.

According to Reporters Without Borders (RSF), his relatives and colleagues have been unable to contact him.

"The disappearance of Moussa Kaka, a well-known journalist, is particularly concerning at a time when Niger is going through a period of heightened political and security tensions," Sadibou Marong, director of RSF's sub-Saharan Africa bureau, said in a statement.

"RSF is following the situation closely and calls on Nigerien authorities to immediately open an investigation in order to find him and establish the circums...