The fall of Aleppo is a turning point. What’s next for Syria’s war?

The fight for Aleppo is over. Bombardment by Syrian and Russian jets and deadly ground operations brought an end to the siege; thousands of civilians are fleeing amid reports of mass killings by government forces and allies. Chief foreign affairs correspondent Margaret Warner reports and Hari Sreenivasan talks to the Middle East Institute’s Randa Slim and University of Oklahoma’s Josh Landis.

HARI SREENIVASAN: The years-long battle for control of Syria’s largest city, Aleppo, is over. A punishing bombardment by Syrian and Russian jets and deadly ground operations brought an end to the siege of the last rebel areas of the city.

It’s a major turning point in the brutal half-decade war.

Chief foreign affairs correspondent Margaret Warner begins our coverage.

MARGARET WARNER: After four years of fighting, the end is at hand in Eastern Aleppo. Word came late today of agreement on a cease-fire and evacuation from the shattered city.

BRITA HAGI HASAN, President, East Aleppo Local Council (through translator): The agreement includes the groups of fighters and the civilians, but my heart is full of pain, full of emotion for having to ask for a complete evacuation of all civilians.

MARGARET WARNER: In addition, Russian officials announced joint military operations with the Syrians against rebel-held Eastern Aleppo have also ended.

Anne Barnard, who has been covering the Syrian conflict for The New York Times in Syria and from Beirut, said the cease-fire assures rebels and civilians they will be evacuated to a safe place.

READ MORE: Fall of Aleppo poses first major test of Trump’s Russia posture

ANNE BARNARD, The New York Times: The plan is for them to go to other rebel-held areas, which had been a demand of the civilians and rebels there because they were afraid that if they went to the government side, as tens of thousands of people have done, they would be arrested or face other reprisals.

Inside the government-held districts of the city, life was going on more or less as normal, but there was the constant danger of shelling from the rebel side.

MARGARET WARNER: In government-held West Aleppo, there was jubilation.

But in the East, thousands of civilians are already fleeing, and there are reports are mass killings by government forces and their allies pouring into the city. U.N. officials say more than 80 people were executed in a single neighborhood, many of them women and children. Other reports told of dozens of children trapped in a building under attack.

Overnight, activists in the city posted grim goodbyes on social media.

WOMAN: We are here exposed to a genocide in the besieged city of Aleppo. This may be my last video.

MAN: We were a free people. We wanted freedom. We didn’t want anything else but freedom.

MARGARET WARNER: The fall of Eastern Aleppo marks a watershed in the five-year Syrian civil war. Opposition forces first took part of the city in 2012.

They prevailed for years, until October 2015, when Russia stepped in to bolster the Syrian military with punishing air assaults. When cease-fire talks brokered by the United States collapsed last month, the onslaught intensified.

At the U.N. today, U.S. Ambassador Samantha Power put the onus on Russia and Syria.

SAMANTHA POWER, U.S. Ambassador to the United Nations: Is there no act of barbarism against civilians, no execution of a child that gets under your skin, that just creeps you out a little bit? Is there nothing you will not lie about or justify?

MARGARET WARNER: Even the fall of Aleppo will not mean an end to the Syrian war. President Bashar al-Assad has vowed to crush the resistance to his rule throughout the entire country. Rebel forces still operating in Northern Syria are bracing for an assault by government troops.

The chief Syrian opposition coordinator insists the loss of Aleppo will not make them give up.

RIAD HIJAB, Chief Syrian Opposition Coordinator (through translator): If Assad and his allies think that a military advance in certain quarters of Aleppo signifies that we will make concessions on the goals of the revolution, that will not happen.

MARGARET WARNER: Meanwhile, Islamic State fighters took advantage of the government’s focus on Aleppo this week to recapture the ancient Syrian city of Palmyra.

For the “PBS NewsHour,” I’m Margaret Warner.

HARI SREENIVASAN: Today, a group of scholars and Middle East experts met at Rice University’s James Baker Institute of Public Policy in Houston to discuss options for the new Trump administration of a region once again transformed by the fall of Aleppo.

Two of those experts join me now, Randa Slim of the Middle East Institute, and Joshua Landis of the University of Oklahoma.

Randa, let me start with you. What does this mean now that military operations are over in Eastern Aleppo?

RANDA SLIM, Middle East Institute: Well, it means this phase of the conflict is over, but, as the Syrian officials have themselves declared, the war is far from over.

What also this win — and it is a win for the regime, political and military win — means is, it spells the end of the negotiation process. Until now, Assad has paid lip service to the idea of negotiations and political process to end the civil war in Syria.

And I think now he’s going to be definitely dead set against it, because he will look at this as, you know, winning, winning this war, and that there’s no need for him to make the necessary concessions to make the political negotiation successful, including, you know, transitioning out of power, which is one of the premise of the political negotiations started in Geneva.

HARI SREENIVASAN: Joshua Landis, what’s the impact of the end of this battle vs. the end of the war?

JOSHUA LANDIS, University of Oklahoma: Well, the center of gravity for opposition now shifts to Idlib province and Idlib city.

That city is dominated by the al-Qaida wing of the opposition and other Salafist forces. The United States and the West cannot support those Salafists and al-Qaida. It means that the rebels are going to have a very hard time getting significant amounts of support.

And it also means on a larger scale that a new security architecture is being laid down in the Northern Middle East, Lebanon, Syria, Iraq, in which pro-Iranian governments are consolidating their grip on the territory and they’re backed by Russia, to a large degree. And this has caused great grief and consternation in Saudi Arabia and amongst many of the United States’ allies, Israel, the Gulf countries, Turkey, because they see this new architecture of security and Iranian influence and Russian influence as something that’s very bad for them.

And the United States’ course is being pulled in to try to counter that.

HARI SREENIVASAN: Randa Slim, as Josh just mentioned, there are so many different actors here. Let’s take them kind of one at a time. What happens to the rebels now after this military setback?

RANDA SLIM: I think they have — they are in for some serious evaluation of their tactics and of, you know, what they have achieved and why they have failed until now, I mean, given the odds they were facing.

Part of them definitely will buy into this idea that, you know, extremism is the way to go. And so the win in Aleppo will fuel the narrative of groups like al-Qaida. And you will see more people maybe being attracted to this idea.

But, also, I think there will be a group of the rebels that need to focus on shifting strategy away from holding territory, and because they cannot do that, you know, when faced with the — with the aggression from the Syrian regime and from the Russian forces, and shift that would — becoming an insurgency, and employing tactics to defeat these forces in a way that make them viable in this battle.

HARI SREENIVASAN: Joshua Landis, what about ISIS and al-Qaida that almost seem forgotten in this giant proxy war? What happens? Is ISIS taking advantage of this opportunity, as Margaret Warner reported?

JOSHUA LANDIS: Yes, ISIS did.

We saw that, as Syrian troops went to Aleppo, ISIS took Palmyra. But ISIS’ days are numbered. The Trump administration has said that they’re going to concentrate on ISIS and they’re going to work with Russia. Now, we don’t know whether they really will work with Russia or not, but it’s clear that ISIS is going to be pounded.

Who is going to benefit from that? It’s quite clear the Syrian regime in Syria, as the Iraqi regime in Iraq is benefiting from America’s effort to destroy those opposition forces in both countries. And there aren’t any other rebel forces that one can foresee on the horizon that will be able to take Eastern Syria that’s now occupied by ISIS.

But the Syrian government will be there. It’s weak today, but it’s been gathering strength. And I think it’s likely that, in the next few years, you will see the Syrian government retake much of Syria. Now, this is disputed amongst experts. There are a lot of people here today at our conference who think that that’s not likely to happen, that there may be enclaves and so forth.

But I think the Assad regime is on a roll. I think it’s got the backing of Russia and Iran and Hezbollah. And it’s hard to see who is going to stand in their way in this steady fight against the insurgents.

HARI SREENIVASAN: Randa Slim, what happens to U.S. support, considering that there is this shift in momentum militarily? What happens to the aid that we’re giving to these rebels?

RANDA SLIM: Look, I mean, we have now a new administration that’s going to take power in January.

And we already have heard from Mr. Trump during the campaign that the priority of his administration will be focusing on fighting ISIS, and that he’s against nation-building, against regime change.

So, I’m going — I would expect us to move into some kind of a security dialogue with the Russians about what to do in Syria. However, the Russians have the baggage. And that’s Iranian baggage they’re going to bring with them with any kind of dialogue with Americans.

And you have already this contradiction between an American administration that wants to engage with the Russians, but also an American administration that sees Iran as a great threat. And so the question is how you’re going to square these two contradictory, in a way, positions and attitudes as you enter into a security dialogue with the Russians.

But when it comes to the support of our allies — and, primarily, the main ally has been the Kurds — I see the possibility, as a result of this American-Russian security dialogue, I see the possibility of the Kurds — of a deal, in a way, being struck, at the expense of the Kurds in Northern Syria.

HARI SREENIVASAN: Joshua Landis, are the Kurds the ones that get squeezed out in this process, where they have to have the support of the U.S. to continue on, but, at the same time, Turkey wants nothing to do in any close independence of theirs?

JOSHUA LANDIS: Well, I do believe that the Kurds are in a difficult situation. They do have some American support. How consistent that will be is unclear.

But they have built up a strong military, and they have begun to build the institutions of an autonomous life in Northern Syria. Turkey’s enmity towards the Kurds and their desire to make sure there is no independent Kurdish state or even really autonomous enclave is going to push the Kurds into Assad’s hands over time.

They’re going to have to strike a bargain with Assad that will keep them in the Syrian state and under some kind of Syrian authority, so that they can have the protection of international legitimacy and the Syrian army against the Turks.

How much — how they can bargain with Assad is unclear. What kind of negotiations they can come to, unclear. We will see whether they get something like the Kurds in Iraq, which is a large measure of autonomy, or something less than that. That will be one of the big negotiations to come out of this process.

HARI SREENIVASAN: All right, Joshua Landis, Randa Slim, thank you both.

JOSHUA LANDIS: Pleasure.

HARI SREENIVASAN: We have more online. Before Aleppo was devastated by war, the city was a thriving hub with a proud history dating back millennia. Find images from before and after the destruction at PBS.org/NewsHour.