Rights group Amnesty International has accused Morocco of denying jailed journalists an academic access to materials so they can read and write, and called for their release.
In a statement, which Moroccan authorities on Thursday rejected, Amnesty said this amounted to a violation of their right to freedom of expression.
"To deprive imprisoned journalists of pens and paper is punitive, unnecessary and a deliberate attack on their freedom of expression," Amnesty's Rawya Rageh said on Wednesday.
Journalists Omar Radi, Soulaimane Raissouni and Taoufik Bouachrine are in prison after being sentenced to five, six and 15 years respectively in cases of sexual assault.
The Amnesty statement also cited human rights lawyer Mohamed Ziane, 80, given a three-year prison sentence for 11 unrelated charges including bogus charges of insulting public officials as well as a charge of sexual assault.
It also mentions writer Rida Benotmane, a member of the Moroccan Association for the Defence of Human Rights (AMDH), who has been in solitary confinement since September 2022.
"He is accused of bogus charges that stem solely from exercising his right to freedom of expression," Amnesty said.
All have denied the charges against them.
Citing relatives, the rights group said the detainees had had manuscripts confiscated and were not allowed to write.
On Thursday the prison authorities denied that Radi was being prevented from writing, saying that "he has pens and paper" as well as books, newspapers and magazines.
No mention was made of the other cases.
The Amnesty statement said the authorities in Morocco must release journalists and academics who were imprisoned solely for exercising their right to freedom of expression and ensure they had access to reading and writing materials.
Morocco says those named had been convicted in cases that had nothing to do with freedom of expression.
In the latest press freedom index from media watchdog Reporters Without Borders (RWB), published on Wednesday, Morocco has slipped down nine places to the 144th spot.
On Thursday, government spokesman Mustapha Baitas said RWB was known for its systematic hostility towards Morocco.
He said the government accepts criticism as long as it is “objective and constructive".