Twenty-four Yemenis, including a teenage girl, could face the death penalty in the rebel-held capital Sanaa on charges linked to their minority Bahai faith, Amnesty International said on Tuesday.
The Bahais, among them eight women apart from the girl, face charges which can carry the death penalty in Yemen, including espionage for a foreign state, the London-based rights group said.
"We are seeing trumped up charges and flagrantly unfair proceedings used to persecute Yemeni Bahais for their faith," said Lynn Maalouf, head of Middle East research at Amnesty.
"It is particularly abhorrent that some of these men and women could face the death penalty for their conscientiously held beliefs and peaceful activities."
Maalouf called for their immediate release, adding that the Iran-backed Huthis should drop the "bogus" charges and "end their abuse of the justice system".
Rights groups have warned the Huthis have cracked down on minorities and journalists in the rebel-held capital since 2015, a year after the rebels drove the government of President Abedrabbo Mansour Hadi out of Sanaa.
The Bahai faith, which has an estimated seven million followers worldwide, emerged in the second half of the 19th century.
The movement is named after Bahaullah, an Iranian born in 1817 whom the Bahais believe is the latest prophet sent by God.
Iran and other states consider the Bahais heretics and suspect many of espionage for Israel, home to a Bahai centre in the northern city of Haifa.
Saudi Arabia and its allies joined the Yemeni government's fight against the Huthis in 2015, triggering a conflict that has killed nearly 10 000 people and what the UN calls the world's worst humanitarian crisis.