Cairo: The United Nations Children's Fund, known as Unicef, said it was "dismayed" by the death of a 12-year-old Yemeni girl, who died three days after being married, and urged the country to take steps to protect child brides.

"The death of Elham Mahdi Al Assi from internal bleeding following intercourse, three days after she was married off to a man at least twice her age, is a painful reminder of the risks girls face when they are married too soon," Sigrid Kaag, Unicef's Regional Director for the Middle East and North Africa, said in an emailed statement.

One out of three girls in Yemen is married before they turn 18, she said, urging authorities to pass and implement laws setting a "reasonable minimum age" for marriage in order to comply with the UN's Universal Declaration of Human Rights, which requires consent to marriage to be free and full.

Widespread

Child marriages are widespread in Yemen, the poorest Arab nation, and were highlighted by the case of another Yemeni child bride, Nujood Ali, who was married off by her parents and then went to court and managed to get a divorce.

Ali's biography, I Am Nujood, Age 10 and Divorced, by Le Figaro's French-Iranian journalist Delphine Minoui, was published in English last month.

Yemen's population is growing three per cent a year, with an average family size of seven, according to the United Nations Development Programme.

Only 34 per cent of women are literate and only three girls attend primary school for every four boys, while the number of women at universities is about one-third that of men, according to the UK's Department for International Development.

Yemen has the highest maternal mortality ratio of the Middle East and North African region with 430 deaths per 100,000 live births, according to the UK government department.