A leading international rights group urged authorities in Yemen on Thursday to set 18 as the minimum age for marriage to improve girls' opportunities for education and protect their human rights. Human Rights Watch said widespread child marriage in the Arab world's poorest country jeopardises Yemeni girls' health and keeps them second-class citizens. A report by the New York group said Yemeni government and UN data showed that in some rural areas, girls as young as 8 were married off. Some told HRW that they were subjected to marital rape and domestic abuse. HRW researcher Nadya Khalife said a ban on child marriage should be a priority for reform despite Yemen's ongoing turmoil that has relegated such issues to "the bottom of the political priority list." The 54-page report was based on field research conducted in Yemen's capital, Sanaa, in August and September 2010, and interviews with more than 30 girls and women who had been married off as children. The report said approximately 14 per cent of Yemeni girls are married before 15, and 52 per cent are married before 18 years old.