A surge of rebel gains in Syria is overturning long-held assumptions about the durability of President Bashar al Assad’s regime, which now appears in greater peril than at any time in the past three years, The Washington Post said.

The capture Saturday of the town of Jisr al Shughour in northern Idlib province was just the latest in a string of battlefield victories by rebel forces, which have made significant advances in both the north and the south of the country.

As was the case in the capital of Idlib province last month, government defenses in Jisr al Shughour crumbled after just a few days of fighting, pointing as much to the growing weakness of regime forces as the revival of the opposition.

The battlefield shifts come at a time when the Obama administration has set aside the crisis in Syria to focus on its chief priorities: defeating the Daesh militant group in Iraq and concluding a nuclear deal with Iran.

Yet the pace of events in Syria may force the United States to refocus on the unresolved war, which remains at the heart of the turmoil engulfing the Middle East, analysts say. Iran backs ­Assad, Saudi Arabia backs the rebels, and a shift in the balance of power in Syria could have profound repercussions for the conflicts in Iraq and Yemen.

“We’re seeing a game changer right now in Syria,” the paper quoted amal Khashoggi, a prominent Saudi journalist, as saying. “I think we are going to see an end to the Assad regime, and we have to think now about what will happen the day after, because the day after is near.”

Other observers say the prospect of a government collapse in Damascus is still remote. The capital is well defended, and the rebels’ gains have come mostly on the periphery of the country, where the regime’s supply lines are stretched.

But perceptions that Assad will survive indefinitely or serve at least as an interim counterbalance to the Daesh group and its strongholds in northeastern Syria are in doubt, said Emile Hokayem of the International Institute for Strategic Studies.

The growing strains on Assad’s manpower and resources “are becoming extremely obvious, and the magnitude of his losses are now too big to hide,” Hokayem was quoted as saying.

“This destroys the narrative that he is winning, which he was counting on, and also the argument that he is the best option against [Daesh],” the analyst added. “If he’s not able to take on or even defend against the rebels, he’s going to have a hard time presenting himself as able to fight [Daesh].”

The revival of rebel fortunes is attributed to a large degree to the recent rapprochement between a newly assertive Saudi Arabia and its erstwhile rivals for influence over the rebels — Turkey and Qatar.

Since inheriting the throne in January, Saudi King Salman has moved forcefully to challenge the expanding regional influence of Iran, Saudi Arabia’s biggest foe, most publicly by embarking on an air war against Iranian-backed Houthi rebels in Yemen. He has also acted to shore up the flagging and deeply divided rebels in Syria, in coordination with Qatar and Turkey, Khashoggi said.

The result has been an unexpectedly cohesive rebel coalition called the Army of Conquest that is made up of al Qaeda affiliate Jabhat al Nusra, an assortment of mostly Islamist brigades and a small number of more moderate battalions. The coalition, which launched last month, has proved more effective than expected.

After seizing most of Idlib province in recent weeks, the rebels are pressing south toward the government strongholds of Hama and Homs and are threatening the ­Assad family’s coastal heartland of Latakia. A separate, more moderate rebel coalition has been making swift advances in the south, challenging government control over the key provincial capital of Daraa and making progress north toward Damascus.