SANAA, Jan 14 (Reuters) - Yemen said it started moving a group of ultra-orthodox Sunni Muslims out of their northern stronghold on Tuesday, under a truce to end months of sectarian clashes with Shi'ite Muslim Houthi rebels.
At least 210 people have been killed in the fighting, which has raised the risk of wider sectarian conflict in a country where instability has already helped al Qaeda militants take root.
The Houthis have long complained about a conservative Sunni Salafi school set up in the middle of their mountain heartland in the northern province of Saada.
Clashes erupted there on Oct. 30 after the Houthis accused the Salafis in the town of Dammaj of recruiting thousands of foreign fighters to attack them in the remote region near the border with Sunni power Saudi Arabia.
Under a ceasefire reached on Friday, the Salafis were given four days to relocate about 250 km (150 miles) southwest to the Red Sea port of Hudaida.
Yehia Abuesbaa, head of presidential committee set up to try to end the fighting, said four army helicopters had moved the head of the school, Yahya al-Hujuri, and his aides.
"The rest of the Salafis, and 97 foreign students studying in Dammaj, will be moved tomorrow," he added.
The sectarian rivalry has cast a shadow over reconciliation efforts in Yemen, a U.S.-ally that is home to one of the most active wings of the Sunni militant force al Qaeda.
The country, in turmoil since a popular uprising ousted president Ali Abdullah Saleh in 2011, is also facing southern secessionists and an economic crisis.
The Salafis, who follow a strict interpretation of Sunni Islam, say the foreigners are students seeking to deepen their knowledge of Islam in the town's Dar al-Hadith seminary.
A number of previous ceasefire attempts have failed to take hold. But Abuesbaa had said the latest one had a better chance of holding because it included all factions involved in the fighting in Saada and adjacent provinces.