Nicosia:
Amnesty on Friday urged the United Arab Emirates to release three sisters detained for the past three months after having campaigned on Twitter on behalf of their jailed brother.
Asma Khalifa al-Suwaidi, Mariam Khalifa al-Suwaidi and Alyaziyah Khalifa al-Suwaidi have been held "in secret detention and with no contact with the outside world" since they were summoned by Abu Dhabi police on February 15, it said.
"The enforced disappearance of these three women is a crime under international law and a shameful act of cruelty," Amnesty International said in a statement.
"The sisters are at risk of torture and other ill-treatment, including sexual violence. They must be immediately and unconditionally released," said Said Boumedouha, the rights group's deputy head for the Middle East and North Africa.
Their brother was among 69 Islamists jailed by Abu Dhabi's state security court for between seven and 15 years on charges of having formed a "secret organisation" to seize power and for contacts with the outlawed Muslim Brotherhood.
Amnesty said UAE authorities were "showing utter disregard for free speech and for those activists who peacefully stand up for their rights and those of their loved ones".
"The treatment of these women is starkly at odds with the progressive image that the authorities seek to project abroad regarding women's rights."