UN envoy quits after criticism

The UN envoy to Yemen has resigned after failing to avert large-scale violence, dealing a blow to hopes of a diplomatic solution to the conflict between rebels and Saudi-backed government forces.

The announcement from the United Nations came as a Saudi-led coalition pressed its air war against the Iran-backed rebels into a fourth week, promising "no half measures" in its campaign to restore President Abedrabbo Mansour Hadi.

As UN envoy, Jamal Benomar had tried desperately to avert all-out conflict as the Shia Huthi rebels seized the capital last September and then placed Hadi under effective house arrest in January.

But Hadi's escape to second city Aden the following month to rally opposition to the rebels effectively brought negotiations to an end and Benomar's efforts to revive them came to nothing as the rebels advanced on the president's last refuge, triggering his flight to Saudi Arabia.

Last month, a Gulf diplomatic official accused the UN envoy of appeasing the rebels and their allies as they overran Saudi Arabia's impoverished but strategically important neighbour.

The Moroccan diplomat had been instrumental in negotiating a peace deal that eased former president Ali Abdullah Saleh out of office in February 2012 after a year of bloody protests against his three-decade rule, and Ban paid tribute to his work.

Among the candidates to replace him is Mauritanian diplomat Ismail Ould Cheikh Ahmed, who currently heads the UN Ebola mission in Accra, a UN official said, speaking on condition of anonymity.