A Rwandan opposition group on Thursday decried what it said was a "sharp deterioration of prison conditions" for its jailed president, Victoire Ingabire, although authorities in Rwanda dismissed the complaint as purely political.
Ingabire was sentenced in December 2013 to 15 years in jail for "conspiracy in harming authorities through terrorism and war" and for playing down Rwanda's 1994 genocide, in which at least 800 000 people were killed by Hutu extremists.
She returned to Rwanda in 2010 to run for election against President Paul Kagame but her party was barred and she was arrested after publicly asking that the perpetrators of crimes against Hutus should also be punished, comments that the authorities said amounted to "genocide denial", a crime in Rwanda.
"Since Friday, July 10, 2015, the management of the central prison in Kigali decided to severely tighten the prison regime of Madame Victoire Ingabire, leader of the United Democratic Forces (UDF), without any explanation," wrote UDF party vice president Boniface Twagirimana.
The party alleged that Ingabire's lawyer had been prevented from meeting with his client, "on the grounds that he had nothing more to do at the prison since his client has already been sentenced".
The letter also alleged that Ingabire's books had been confiscated and she was prevented from speaking with visitors. Twagirimana said the new measures were "draconian" and "amount to mental torture".
But the head of the country's prison service, Paul Rwarakabije, dismissed the complaint.
"This open letter from this party, which is not currently recognised in our country, is a tract," he told AFP in Kigali, explaining that Ingabire's lawyer had been denied access because he had visited the prison outside the normal visiting hours.