An image from AFP TV, taken on Saturday, shows Huthi rebel fighters riding on the back of a pickup truck and flying the group’s flag in Yemen’s capital, Sanaa. (Stringer/ Agence France-Presse/Getty Images)

Days of fierce clashes here in Yemen’s capital have opened a violent new front in the country’s multisided civil war, with an alliance of Yemeni forces battling a Saudi-led military coalition fracturing — a potentially major shift in the conflict.  

The latest clashes have pitted a Yemeni rebel group known as the Houthis against forces loyal to Ali Abdullah Saleh, the former president of Yemen who was ousted five years ago but continues to wield outsized influence.

Dozens of people have been killed in the fighting, which started Wednesday. The clashes started with a standoff at a mosque in Sanaa, according to officials in the capital. But like most episodes in the war, the exact cause remained murky, and there was immediate suspicion that Saudi Arabia and its allies, including the United Arab Emirates, had played a role in turning Saleh against the Houthis. 

 In the days before the clashes, Saudi officials had referred obliquely to imminent developments in the war that would improve their fortunes. It was unclear, however, whether they were orchestrating the latest drama or reacting to rumors from the ground.

Through the week, the fighting roared through southern neighborhoods of Sanaa as mediators tried in vain to defuse the crisis. By early Saturday morning, the battle had widened, and residents of the city were jolted awake by the sound of heavy artillery shelling. 

Yemen’s former president, Ali Abdullah Saleh, delivers a speech on Aug. 24. (Arhab/European Pressphoto Agency-Efe/Rex/Shutterstock)

“Dozens killed in fierce fighting in Sanaa, #Yemen. Hundreds more injured,” the local chapter of the International Committee for the Red Cross wrote on Twitter on Saturday. “Our call to all parties: Civilians are not part of the fight.”

It remained to be seen whether the latest violence would alter the trajectory of the conflict. The Houthis and Saleh are uneasy allies and have feuded in the past. But harsh accusations by leaders of the two camps on Saturday, and the intensifying skirmishes, signaled a possibly irreparable rift between the two sides. 

 In a televised speech Saturday, Saleh blamed the Houthis for the violence and called on his forces to ignore orders from the Houthi leadership. “Yemeni citizens have tried to tolerate the recklessness of the Houthi militias over the last two and half years but cannot anymore,” he said.

Saleh — a wily dealmaker whose greatest achievement, arguably, has been ensuring his own political survival — also addressed the Saudi-led coalition, calling on them to stop their “aggression” in Yemen and begin negotiations to “start a new page.”

The Houthi rebel leader, Abdulmalik al-Houthi, also spoke on television Saturday, insisting that his forces had practiced restraint and been surprised by the attacks their erstwhile allies.

The “wise people of Yemen,” he said, needed to “investigate who is behind the strife.” 

The Houthis and Saleh forces have long been allies in the civil war, which began in 2015 and has claimed the lives of more than 10,000 people. Together, they have clung to large swaths of territory in northern and central Yemen while fending off attacks by the military coalition — led by Saudi Arabia and backed by the United States — which controls Yemen’s skies, borders and seaports.

The stalemated conflict, which has spawned a vast humanitarian crisis in the Arab world’s poorest country, has alarmed aid organizations and embarrassed Saudi Arabia, which has cast Yemen as a critical front in its conflict with its regional enemy, Iran. The Saudis have accused Iran of directly supporting the Houthis, including by providing weapons. The Houthis have denied accusations that they serve as an Iranian proxy force.

In a statement, the Saudi coalition praised the “uprising” by members of Saleh’s political party against the “evils of Iranian terrorist and sectarian militias.” The shift in tone was evident on al-Arabiya, a Saudi-owned news channel, which played Saleh’s statement repeatedly and referred to him as the “former president,” rather than the “ousted president,” as had been the channel’s previous practice. 

Fahim reported from Riyadh, Saudi Arabia