SANAA (Reuters) - Shi'ite Muslim Houthi rebels backed by tanks launched a fresh attack on Friday on a town in north Yemen held by their Sunni Muslim Salafi rivals, a Salafi spokesman said, bringing the total death toll in three days of sectarian clashes to 40.
The fighting erupted on Wednesday despite government mediation efforts to shore up a ceasefire in place since late last year in the mountainous Saada province, which has long been outside the control of the central Yemeni authorities.
Salafi spokesman Abu Ismail al-Hajouri told Reuters the casualties were all Salafis and that at least 200 more people had been wounded during the Houthi offensive against the town of Damaj.
Damaj lies near Saada, a Houthi-controlled city near the Saudi border 130 km (80 miles) north of the capital Sanaa.
Saada province is the base for a long-running Houthi rebellion against the Yemeni government. Saudi Arabia's military intervened in 2009 before a ceasefire took hold the year after. The province has since fallen openly into Houthi hands with a Houthi-imposed governor.
Hajouri said Damaj had been besieged by Houthi rebels for weeks and accused them of shelling the city with rockets that set on fire dormitories for students at a religious school.
Houthi officials could not be reached for comment. There was no independent account of the clashes and no immediate report of any Houthi casualties.
A Houthi statement on Wednesday accused the Salafis of igniting strife by bringing thousands of foreign fighters to Damaj.
The Salafis say the foreigners are students there to study Islamic theology in a seminary built in the 1980s.
The Houthis blockaded Damaj for weeks last year, accusing the Salafis of stockpiling weapons, a charge they deny.
Some Sunnis fear the Houthis want to revive the 1,000-year Zaydi Imamate, whose rulers claimed descent from the Prophet Mohammad. The imamate ended in a 1962 military coup.
Apart from the Salafi-Houthi conflict, Yemen is struggling with southern secessionists and militants of al Qaeda in the Arabian Peninsula, which has plotted attacks on U.S. airliners and targets in Saudi Arabia, the world's top oil exporter.
(Reporting by Mohammed Ghobari; writing by Rania El Gamal, editing by Gareth Jones)