Thirty-two human-rights groups launched a campaign Thursday over a detained Mauritanian blogger who was entitled to release a year ago after his case of blasphemy was settled.
"Although authorities should have released him in November 2017, Mohamed Mkhaitir is still being detained in an undisclosed location," they said in a joint statement.
"His physical and mental health are deteriorating as a result of his prolonged detention."
Mkhaitir, 35, was pitched into a storm in the conservative Muslim nation over a blog post deemed to insult the prophet Mohammed.
Amid protests and outrage, he was arrested in January 2014, put on trial in December 2015 and charged with apostasy, before being sentenced to death the following day.
On November 9 2017, after Mkhaitir repeatedly repented, an appeal court overturned the ruling and handed him a two-year prison service -- which he had already served -- and a fine.
Amnesty International, one of the signatories, said lawyers have repeatedly requested to visit him but not received an answer from the ministry of justice.
In May, the Mauritanian authorities said Mkhaitir -- also spelt Mkheitir and M'Kheitir -- was being held in "administrative detention for his own safety."
Angry protests unfurled in Mauritanian towns when Mkhaitir was put on trial and after his sentence was announced.
The National Assembly, in April this year, passed a law making the death penalty mandatory for convictions for "blasphemous speech" and "sacrilegious" acts, even if the offender promptly repents.
The last execution in Mauritania took place in 1987.
Mkhaitir's case contributed to Mauritania falling 17 positions in Reporters Without Borders' 2018 World Press Freedom Index, the biggest drop of any African nation.