GWEN IFILL: Now to Syria, with two reports from inside Aleppo, as the nation's largest city endures its tenth day of fierce battle between government troops and rebels.
The fighting there has centered in the southwestern neighborhood of Salahuddin. The United Nations reports that 200,000 of the city's 2.5 million residents have already fled.
We begin with John Ray of Independent Television News.
JOHN RAY: The battle for these streets could yet decide fate of all Syria. So, rebels fight hard to retain a foothold at the heart of the city, while state TV shows Assad's soldiers hunting them down.
If this scene looks slightly staged, in the past few days, we have witnessed the awesome reality of the regime's firepower. On the outskirts of Aleppo, we come under a barrage of shell and rocket attacks, a bombardment that last several hours.
At dawn, thick smoke fills the air. And terrified, the few remaining residents are packing up to leave, joining an exodus the U.N. says is 200,000 strong.
The streets around me here are now almost entirely deserted, except for a few Free Syrian Army fighters. That's a suburb of 30,000 people that has emptied out as the fighting has intensified in the city below. And about a kilometer from here, dug in, a detachment of Syrian army tanks.
Today, a fierce firefight said to be at a checkpoint to the north of the city, rebels claim victory here, looting weapons and ammunition, celebrating on top of a captured tank. The regime cannot afford to lose Aleppo. It says it's purging Syria's second city of terrorists. So much disputed, only one certainty: more bloodshed and more names to carve on gravestones, though, in this town, we're told, the stone mason has already run for his life.
JUDY WOODRUFF: And to a second report from Aleppo.
Margaret Warner spoke to James Foley from our partner GlobalPost. They talked via Skype earlier today.
MARGARET WARNER: James Foley, thanks for speaking with us.
So what's the state of the conflict right now between the rebels, who came in about 10 days ago, and the government forces now mounting this assault?
JAMES FOLEY, GlobalPost: We hear a lot about the battle for Aleppo as being one of the critical battles.
And it seems like the Syrian army is trying to really demoralize the rebels by using Syrian fighter jets. We saw MiG fighter jets yesterday swooping down, firing missiles and rockets, followed by of course helicopters that they have used for a while now. So this is a terrifying tactic.
They have also made tank probes into places like Salahuddin. A lot of activists speculate that the real battle hasn't started yet, they're just testing the area.
It would seem that, if Assad loses Aleppo, surely this is a huge blow for him, and he wouldn't be able to tolerate that, Aleppo being the industrial capital.
MARGARET WARNER: Assad used to enjoy support from the business community in Aleppo. What can you tell about how the population feels now, where their sympathies lie?
JAMES FOLEY: We were here weeks before fighting broke out. And it was very interesting, because there's wealthiest neighborhoods in Aleppo that look like Amman or Beirut untouched by fighting, untouched by protests, wealthier shops, and, of course, very nice homes.
And the question is, have these people gone, fled to Lebanon? Have they fled to Turkey? Or are they just staying in their houses for now to see what happens? There's still power in these parts of the city. They're not being shelled. And there are still army positions. The places that are shelled, as I said, are beginning to look like the worst war zones in Syria now.
MARGARET WARNER: Well, James Foley, thanks so much for doing this. And stay safe.
JAMES FOLEY: Thanks. I appreciate you guys.
GWEN IFILL: There was another high-level defection from the Syrian government today. The top diplomat in London said he would no longer represent the Assad regime.