Yemen's Shia and Sunni Muslim fighters have agreed to a ceasefire after days of clashes that killed at least 100 people.

The truce was announced on Monday by the UN envoy to Yemen, who said the country's president, Abdrabuh Mansur, had sent a plane to collect the wounded from the town of Damaj.

"I hope this ceasefire will be permanent, and I hope that efforts will follow to find a solution for the roots of this problem," Jamal Benomar said while warning the conflict "threatens the security of Yemen".

The agreement to end the fighting allowed Red Cross aid workers to enter the town to treat wounded civilians, but a translator with the team was shot dead, said Surour al-Wadi'i, a Sunni Salafi spokesman.

Start of latest clashes

The clashes in Damaj broke out on Wednesday when Shia Houthi fighters, who control much of the border province of Saada, accused their Sunni Salafi rivals of recruiting thousands of foreign fighters to attack them.

The Salafis said the foreigners were students who travelled from abroad to study Islamic theology at Dar al-Hadith academy.

"There were massive Houthi attacks throughout the night against Dar al-Hadith academy and student dormitories," said Surour al-Wadi'i. "The death toll has risen to at least 100."

The figure cited was for Salafis killed in the clashes. The Houthis have not issued figures for casualties on their side.

Sectarian rivalry in Damaj has cast a shadow over reconciliation efforts in Yemen, a neighbour of oil exporter Saudi Arabia and home to one of al-Qaeda's most active wings.

The fighting has caused concern among world powers that helped ease long-ruling President Ali Abdullah Saleh from power in 2011 after months of protests.

Source: Agencies