Yemen rose sharply up the regional security agenda in August when the government launched Operation Scorched Earth against Muslim Shi'ite rebels in the north, prompting the bloodiest episode in a conflict dating back to 2004.

It rose higher still this month when rebels seized some Saudi territory, killing two border guards, and accused Riyadh of allowing Yemeni forces to use Saudi land as a launchpad for their attacks against them.

Saudi Arabia responded by launching a military assault on the rebels -- known as the Houthis after the clan of their leader -- and enforced a 10 km (six mile) deep buffer zone inside Yemen to keep rebels away from its southwestern border.

The violence has displaced more than 170,000 civilians, who face malnutrition and cholera, the United Nations says.

The rebels, from the minority Zaidi sect of Shi'ism, say they face political, economic and religious discrimination from the Yemeni government, which they accuse of favouring the radicals among the Sunni majority who lean towards Saudi Arabia's puritanical Wahhabi Islam.

[link to www.reliefweb.int]