Amnesty International has called for Houthis in Yemen to immediately release a human rights activist abducted by two militants.
On its website, the London-based rights group wrote: "Kamal Al-Shawish, a field research assistant with Mwatana Organisation for Human Rights in the city of Hudaydah, was seized on the street by two Houthi armed men on Tuesday. He was blindfolded and taken to an unknown location. His whereabouts remain unknown."
The organisation said that the activist had documented human rights violations against civilians in the Red Sea port town prior to his arrest.
Lynn Maalouf, Amnesty International's deputy director for Research in the Middle East and North Africa, said: "The worrying abduction of Kamal Al-Shawish seems to be part of a sinister pattern of harassment and repression of human rights work in Yemen, committed by all sides to the conflict."
"The Houthi armed group must reveal his fate and whereabouts and ensure he is protected from the kind of torture and ill-treatment that has been inflicted on others in its custody. Kamal Al-Shawish should be released immediately."
Throughout the conflict in Yemen, Amnesty said, human rights defenders and journalists have been harassed, threatened, beaten, arbitrarily detained and forcibly disappeared in both government and Houthi-controlled territory.
According to the organisation, Mwatana has been particularly targeted, with the organisation's Executive Director Abdulrasheed Al-Faqih and Chairperson Radhya Al-Mutawakel both briefly detained in June.
They were given no reasons for their arrest, the organisation said, but were told that they were not permitted to travel and were being arrested at the behest of the Saudi Arabia and the United Arab Emirates (UAE)-led coalition.
"Houthi and government forces in Yemen must end their harassment and intimidation of human rights defenders who are simply exercising their right to freedom of expression by trying to report on what is going on in the country," Maalouf said.