Human rights experts working for the United Nations on Monday urged Yemen’s Houthi rebels to release five people from the country’s Baha’i religious minority who have been in detention for a year.

Human rights experts working for the United Nations on Monday urged Yemen’s Houthi rebels to release five people from the country’s Baha’i religious minority who have been in detention for a year.

The five are among 17 Baha’i followers detained last May when the Houthis raided a Baha’i gathering in the capital of Sanaa. The experts said in a statement that 12 have since been released “under very strict conditions” but that five remain “detained in difficult circumstances.”

There have long been concerns about the treatment of the members of the Baha’i minority at the hands of the Yemeni rebels, known as Houthis, who have ruled much of the impoverished Arab country’s north and the capital, Sanaa, since the civil war started in 2014.

The experts said they “urge the de facto authorities to release” the five remaining detainees, warning they were at “serious risk of torture and other human rights violations, including acts tantamount to enforced disappearance.”

A spokesman for the Houthis did not return a request for comment.

The 12 were released only after signing a pledge not to communicate with other Baha’is and “refrain from engaging in any Baha’i activities,” the experts said. They are also not allowed to leave their hometowns without permission.

The experts are part of the Special Procedures, which is the largest body of independent experts in the United Nations Human Rights system.

The Houthis have waged an all-out campaign against all political and religious opponents and have held thousands in detention, where torture is rampant.

The Baha’i have been particularly vulnerable to persecution and pressure to convert to Islam by the Houthis who consider their religion heresy.

Baha’i is a monotheistic religion founded in the mid-19th century by Baha’u’llah, a Persian nobleman considered a prophet by the Baha’is. He taught that all religions represent progressive stages in the revelation of God’s will, leading to the unity of all people and faiths.