Houthi rebels in Yemen have carried out a wave of arrests of their opponents, seizing them at gunpoint and torturing some, Amnesty International says.
An examination of 60 cases revealed a pattern of arbitrary arrests and enforced disappearances, according to a new report by the human rights group.
Politicians, journalists, academics and activists have been among those held.
The Houthis, who control the capital Sanaa, are waging a war against Yemen’s government and a Saudi-led coalition.
At least 6,200 people, half of them civilians, have been killed and almost three million others have been displaced since March 2015.
The conflict has also pushed the Arab world’s poorest country to the brink of famine and left 82% of the population in need of humanitarian assistance.
Amnesty’s report documented what it described as a “chilling campaign to quash dissent” in areas of Yemen under the control of the Houthis and allied security forces loyal to former President Ali Abdullah Saleh since December 2014.
Those held had frequently been tortured and denied access to a lawyer or their family, with some detentions lasting for up to 18 months, it said.
Many had been kept in secret, makeshift detention centres, including private homes, and then transferred multiple times between locations, it added.
In the vast majority of cases no reason for arrests were given.
Eighteen individuals featured in the report are still being held, including 21-year-old student Abdul Ilah Saylan, who was arrested outside a Sanaa cafe last August.
Members of his family told Amnesty how members of the security forces had tortured him in front of them when they visited him in detention in February.
“The guard began to beat him. Three other guards joined in and we watched… as the four guards beat him viciously,” one relative was quoted as saying.
“They dragged him back inside when he fainted and told us to go home.”
Earlier this month, Houthi officials told Amnesty that people had been detained “because they gave GPS co-ordinates to the Saudi Arabia-led coalition”.
But Amnesty said it had obtained documents showing that prosecuting authorities in Sanaa had found that the detention of dozens of those held was without legal basis and had ordered their release.
“Instead of incarcerating opponents for weeks or months on end, the Houthi armed group should release anyone who has been arbitrarily detained, implement safeguards to ensure detainees are treated humanely, and issue clear instructions that anyone under their command committing abuses will be held accountable,” said Amnesty’s Middle East deputy director James Lynch.