A new ceasefire has been reached between Shiite Huthi rebels and Sunni Islamists fighting in northern Yemen, UN special envoy Jamal Benomar said on Monday.
"I am happy to say that following intensive efforts... we have reached a ceasefire" between the sides fighting in Saada province, Benomar told reporters.
A Red Cross convoy had entered the village of Dammaj, where the Sunni Islamists are besieged by the Huthi rebels.
Benomar said Yemeni President Abdrabuh Mansur Hadi had dispatched a special plane to evacuate the wounded.
"I hope this ceasefire will be permanent, and I hope that efforts will follow to find a solution for the roots of this problem," Benomar said while warning the conflict "threatens the security of Yemen".
"Large groups of gunmen are being mobilised from different areas. This would have serious security implications," he added.
Dammaj, where a school for Sunni preachers has operated since the 1980s, has been the scene of frequent clashes between Sunni Islamists and the Huthis, for whom Saada is a stronghold.
Tribal sources have said at least 11 people were killed in fighting last week, but Sunni Salafist Islamists have put the death toll at around 50.
The fighting with mortar and rocket fire in the past week has been concentrated on the Mazraa mosque and a Koranic school held by the Islamists in Dammaj and surrounded by rebels.
On Saturday, the Yemeni defence ministry's news website reported a ceasefire and said troops had been deployed in areas evacuated by the rival sides.
A statement issued by the Huthi rebels accused Sunni extremists of having "transformed the centre of Dammaj into a real barracks for thousands of armed foreigners."
The Huthis, who are members of the Zaidi Shiite community, rose up in 2004 against ex-president Ali Abdullah Saleh's government, accusing it of marginalising them politically and economically.