(Recasts after men released)
NIAMEY, Feb 13 (Reuters) - Authorities in Niger released on Thursday three journalists from a private radio station one day after they were detained with a union leader who criticised President Mahamadou Issfouou on air, the station's director-general told Reuters.
Police on Wednesday arrested the Anfani radio station's editor in chief Abdoul-Razak Idrissa, and two journalists, Haoua Maigari and Moussa Hassane as well as union leader Ismael Salifou.
Salifou was accused of making insulting remarks about the president and inciting ethnic hatred during the interview broadcast on January 22. The journalists were held as accomplices, police sources said.
"The three journalists employed by my radio station were released. They were brought before the prosecutor of the Niamey correctional tribunal this afternoon and he decided there was no case to answer," said Grema Boukar, director general of Anfani. Salifou was also released, he said.
Political tensions have risen in Niger since August, after a reshaping of Issoufou's ruling coalition that saw National Assembly leader Hama Amadou enter the opposition.
Since late January, six journalists, two politicians and a member of civil society have been briefly detained on charges including slander, inciting ethnic hatred and plotting against state security. They have all subsequently been released.
"Niger is witnessing a decline in freedom of the press. We will fight until our comrade Ismael Salifou is freed," Salou Yacouba, spokesman for the national association of education workers, told journalists.
Niger decriminalised slander in June 2010. (Reporting by Abdoulaye Massalaki; Writing by Daniel Flynn and Matthew Mpoke Bigg)