The war in Yemen, the Arab world’s most destitute country, plunged into a new and uncertain chapter today when its former president was killed amid an explosive bout of fighting that has convulsed the capital.

The death of the former president, Ali Abdullah Saleh, a wily and cunning strongman who had repeatedly switched sides in a bid to regain power, was reported by the rival factions that have been battling in the capital, Sanaa, for days, leaving dozens of people dead.

Yemen’s Houthi rebels, Saleh’s one-time allies who turned on him after he reached out to their enemy, Saudi Arabia, said they had ambushed and killed him in a rocket-propelled grenade assault on his motorcade, apparently as he was trying to flee to an area outside Sanaa. Other accounts said Saleh had been shot.

The precise details of how he died, and who killed him, could not be immediately confirmed.

But video showing the lifeless body of Saleh, 75, with what appeared to be a severe head wound, was posted on the internet early Monday. U.S. intelligence officials who have been monitoring the mayhem confirmed his death.

Saleh, who ruled Yemen for more than three decades, was among the strongmen caught in the Arab Spring uprisings of 2011. He finally left power in early 2012, but retained a strong influence with many armed loyalists in the country.

His demise was likely to compound the escalating tensions between Saudi Arabia and Iran, its regional rival, which has backed the Houthis in the catastrophic civil war that has gripped Yemen since the spring of 2015.

Analysts said Saleh’s death further diminished hopes of a resolution to the conflict, which has created one of the world’s worst humanitarian crises, with 80 percent of the population in need of emergency help. It could easily kick off new violence between Saleh’s supporters and Houthi militants.

“The war will likely become more fierce,” said April Longley Alley, a senior Yemen analyst with the International Crisis Group. “This adds to layers of revenge in Yemen.”

Saleh was killed within hours of an explosion at his family’s compound. Just two days earlier, he had appeared to betray the Houthis and to signal a willingness to reconcile with the military coalition led by Saudi Arabia that has been bombing them repeatedly.

Which side may have caused the explosion at Saleh’s house — Houthis angry at his betrayal or the Saudi-led bombing campaign — was not immediately clear.

As president, Saleh had been a close ally of both Saudi Arabia and the United States, which considered him a partner in the fight against al-Qaida’s affiliate in Yemen and a bulwark against the influence of Iran.

After he agreed to leave office in a deal to end the Arab Spring uprising in Yemen, however, Saleh struck an alliance with the Houthis.

In 2015, forces loyal to him helped the Houthis seize control of the capital and much of the country. In retaliation, Saudi Arabia, backed by the United Arab Emirates and other Arab Gulf countries and with help from Washington, launched an air campaign.

On Saturday, Saleh appeared to change sides once more. In a televised speech, he blamed what he called the “idiocy” of the Houthis for the years of war in Yemen. He said he was ready to turn a “new page” in his relationship with the Saudi-led coalition if its forces ceased attacking Yemen. The Saudis welcomed his statement.

Last month the Saudis imposed a severe blockade on all of Yemen’s ports after the Houthis had fired a missile into Saudi Arabia, drastically worsening the humanitarian crisis in the country. The Saudis have eased the blockade in recent days, but the United Nations and emergency aid groups say shortages of food and medicine are threatening millions of civilians.

The disastrous consequences of the Saudi blockade appeared to have an effect on Saleh, who once compared his years in office to “dancing on the heads of snakes.”

“I call upon the brothers in neighboring states and the alliance to stop their aggression, lift the siege, open the airports and allow food aid and the saving of the wounded,” he said in the televised speech Saturday, “and we will turn a new page by virtue of our neighborliness.”

The Saudi-led coalition, reacting to Saleh’s entreaty, said it was “confident of the will of the leaders and sons” of Saleh’s political party to lay the groundwork for a rapprochement.

The weekend maneuvering came as Saleh’s supporters fought Houthi adversaries for a fourth day in Sanaa. At least 80 people were reported killed as the fighting threatened to escalate.

On Sunday, Houthi rebels said they had fired a cruise missile at a $20 billion nuclear power plant under construction in Abu Dhabi, the United Arab Emirates, which is allied with Saudi Arabia. But a state-run news agency in the United Arab Emirates denied the assertion.