At least 25 people have been killed and dozens wounded in northern Yemen in what Sunni Islamist Salafi fighters said was shelling by Shi'ite Muslim rebels on Saturday and Sunday.
The shelling killed 10 people on Saturday and continued on Sunday afternoon, a Salafi spokesman said, bringing the death toll to 25 with a further 48 wounded in the latest flare-up in Damaj, about 150 km (90 miles) north of the capital Sanaa. The defence ministry put the death toll at 32.
A Houthi representative disputed the Salafi account of the fighting and said its side had suffered deaths and injuries.
The conflict in the north, where government troops also tried to crush Shi'ite Houthi rebels before a cease-fire last year, is one of several plaguing Yemen which plans elections next year to replace President Ali Abdullah Saleh.
Saleh agreed this week to step down after 10 months of protests to end his 33-year rule. He returned to Yemen late on Saturday, Yemen's state news agency reported, from Saudi Arabia, where he signed the accord that aims to ease him from power.
State television on Sunday broadcast footage of him addressing a group of political allies, and saying protests against him should now end. The country can't take more of what it's been through over the last 10 months, he said.
Saleh also issued a pardon for those who committed acts of idiocy during the country's political crisis, excluding those involved in crimes or an attack on his compound -- an apparent assassination attempt -- that forced him to seek medical treatment in Saudi Arabia in June.
It was not clear whether the pardon would have any practical impact. Saleh's opponents have criticised his public interventions since signing the deal -- which leaves him with his title for now -- as signs he may try to subvert the transfer plan, which he has backed out of three times.
Medical sources and activists in Taiz -- a hotbed of protests against Saleh -- said one person was killed when government forces fired artillery rounds at tribesmen in the city's al-Hasab district.
The deputy to whom Saleh transferred power, Abd-Rabbu Mansour Hadi, on Saturday set February 21 for the presidential election. Yemeni opposition parties have picked a former foreign minister to form a new government envisioned by the deal.
Yemen's neighbours, along with Washington and the United Nations, which echoed a Gulf power transfer plan in a Security Council resolution, hope a political process can halt a slide towards civil war in an impoverished country awash with weapons.
SECTARIAN FIGHTING FLARES NEAR SAUDI BORDER
Regional powers, including the world's biggest oil exporter Saudi Arabia, fear a political vacuum in Yemen will embolden al Qaeda's Yemen-based wing.
Months of political paralysis over Saleh's fate have led to periodic shutdowns in the oil industry Yemen depends on for export revenue, while conflict with a long-standing separatist movement and militant Islamists in the south have flared anew.
In recent weeks, the Houthis have clashed with Salafi fighters, leading local tribesmen to craft a truce between them. It seemed to collapse on Saturday when, Salafi spokesman Abu Ismail said, Houthi fighters had shelled the town of Damaj.
Members of the Zaidi sect of Shi'ite Islam, the Houthi rebels led an uprising based in the northern Saada province that Saleh's forces struggled to crush, with Saudi Arabia intervening militarily in 2009 before a cease-fire took hold the next year.
The Houthis, who effectively control the northern Saada province, are deeply wary of Saudi Arabia's promotion of puritanical Sunni Salafi creeds that class Shi'ites as heretics.
Dayfallah al-Shami, a member of the Houthis' political office, disputed the Salafi account of the fighting. He told Reuters that Houthi leader Abdelmalek al-Houthi had issued orders for a cease-fire but the Salafis had rejected it and fought on.
We have martyrs and wounded, he said. We have informed the mediators that the Salafis can have their slogans as long as they refrain from incitement and takfir (denouncing a Muslim as an infidel).
The representative of the Salafis, who identified himself as Abu Ismail, said six foreign nationals -- of the United States, Indonesia, Malaysia and Russia -- were among the dead after shells hit the grounds of a religious school, Dar al-Hadith, in Saada, which lies in Yemen's northwest and borders Saudi Arabia.
A defence ministry website said the Houthi fighters had used tanks and artillery, and that more than 50 were wounded.
A Houthi official, Saleh Habra, has accused the Yemeni government of arming their Salafi foes, who he said were constructing a military camp near the Saudi border.
(Writing by Joseph Logan; editing by Philippa Fletcher)