Amnesty International on Wednesday accused Yemeni rebels of carrying out a "brutal" campaign of arbitrary arrests and torture of opponents since they seized the capital Sanaa in 2014. Shiite Houthi insurgents, who are backed by troops loyal to ousted president Ali Abdullah Saleh, have "carried out a wave of arrests of... opponents, arbitrarily seizing critics at gunpoint and subjecting some to enforced disappearance," the rights watchdog said. Amnesty, in a statement, said "a spree of arbitrary arrests, disappearances and torture by Houthi forces to persecute opponents" was part of a "chilling campaign to quash dissent." Its report, named "Where is my father? Detention and disappearance in Houthi-controlled Yemen," was based on detailed examination of 60 cases of detention in Taiz, Ibb and Hodeida, Amnesty said. The warring parties at talks in Kuwait have discussed a deal to release half of the detainees and prisoners they hold before the start of the Muslim holy fasting month of Ramadan in early June. But the deal was in jeopardy on Tuesday after Yemen's government suspended its participation in the peace talks, ongoing since almost a month. The Iran-backed Shiite rebels overran Sanaa in September 2014 and went on to expand their control in the impoverished country, advancing to southern provinces. "Houthi forces have presided over a brutal and deliberate campaign targeting their political opponents and other critics since December 2014," charged regional deputy director James Lynch. "Enforced disappearance is an abhorrent crime and cannot be justified under any circumstances," he said. Amnesty said that some detainees have been held for up to 17 months without being brought before a prosecutor or a judge. It said the majority of those targeted are activists, journalists and figures affiliated to the Islamist party Islah (reform). A Saudi-led Arab coalition launched in March 2015 a military campaign against the rebels. Loyalists have since managed to push rebels out of Aden and four other southern provinces, but the Houthis and their allies remain in control of Sanaa and the bulk of the north. The conflict has left more than 6,400 people dead and 2.8 million displaced since March last year, according to the United Nations.