GENEVA (Reuters) - The United Nations Committee against Torture on Friday called on Bahrain to release prominent activist Nabeel Rajab from more than nine months of solitary confinement and investigate widespread allegations of ill-treatment and torture of detainees.

Bahraini human rights activist Nabeel Rajab arrives for his appeal hearing at court in Manama, in this file photo dated February 11, 2015. REUTERS/Hamad Mohammed/File Photo

Bahrain’s mainly Shi’ite Muslim-led opposition has faced a government crackdown since last year in the Sunni-ruled Gulf kingdom. The Western-allied government closed down the main opposition al-Wefaq group, arrested Rajab and revoked the citizenship of Shi’ite spiritual leader Ayatollah Isa Qassim.

The United Nations panel, composed of 10 independent experts, conducted its first review of Bahrain’s record in five years at a session ending on Friday.

Abdulla Faisal Aldosari, the Assistant Minister of Foreign Affairs who led Bahrain’s delegation, said it faced national security challenges but was acting on torture complaints. So far 52 cases had been brought to criminal courts in which 101 suspects had been found guilty of torture, he said.

The U.N. experts, in their findings, urged authorities to “put an end to the solitary confinement of Mr. Nabeel Rajab and ensure that he is provided with adequate medical assistance and redress”.

His solitary confinement “is reported to have exceeded nine months during which he has been denied adequate medical care”.

The U.N. experts cited “continued, numerous and consistent allegations of widespread torture and ill-treatment of persons deprived of their liberty in all places of detention” in Bahrain. A “climate of impunity” seemed to be prevailing, with few convictions and light sentences, they said.

The panel voiced concern at reports of coerced confessions obtained under torture, including those of three men executed in January and two men facing the death penalty, Mohammed Ramadhan and Hussain Ali Moosa. The panel suggested that the latter be retried.

It also said that Bahrain should ensure that people arrested on criminal charges, including under the terror act, be brought before a judge within 48 hours.

Authorities should also consider repealing provisions that allow civilians to be tried in military courts and improve conditions, especially in Jaw prison where inmates rioted in January.

Human Rights Watch, in a statement, quoted family members of 12 opposition activists held in Jaw Prison as saying the men are shackled whenever they leave their cells, including for medical visits. The men are serving long prison terms in connection with the pro-democracy uprising in 2011.

“Authorities can take reasonable measures to prevent escapes, but shackling infirm patients, many of them torture victims, clearly goes beyond any need for security,” it said.