Shortly afterwards, ISIS fighters were on the front lines elsewhere in the city, which proved crucial in helping moderate Free Syrian Army fighters wrest the Minnagh air base from regime control.

As foreign extremists pour into Syria, the country has become what many describe as the new global center of jihad. The two biggest groups operating in the country are Jabhat al-Nusra and ISIS, who are now seeing their ranks swell and civilian support grow as the more moderate opposition struggles.

We asked Aaron Y. Zelin, Richard Borow fellow and jihad expert at The Washington Institute for Near East Policy, about the state of Syria’s jihad.

Syria Deeply: Will we eventually see a jihadi state in parts of Syria? Is that where this is headed?

Aaron Y. Zelin: In terms of a full-blown state similar to the Taliban, I think it’s still too early to tell. What you should remember at this juncture is that they suspend the hudud during war, which is corporal punishment – they’ll stone you or chop your hand off. We’ve seen jihadis utilize that type of punishment in the past in Iraq, Yemen, Somalia, and Mali. People don’t like that. So while Syrians are OK with jihadists providing social services and protecting them, there’ll be more of a backlash if they push their more conservative social mores on people or install the more narrow elements of Sharia law. But at this juncture, as long as they don’t do that, which they probably won’t until they believe they’ve defeated the regime, I don’t think we’ll see anything that hardcore.

The movement itself has learned from its experience in Iraq. ISIS is more intense than Jabhat al-Nusra, but still more or less not doing anything totally crazy. They’re not targeting Sunni civilians, they’re really only going after security forces of the regime, their allies and some Alawites. In terms of the community they’re trying to be a part of, you don’t see anything that excessive.

SD: What’s the state of the relationship between the groups?

AZ: There’s still a rivalry between [ISIS leader Abu Bakr] al-Baghdadi and [Nusra head Abu Mohammed] al-Golani, but when you look at soldiers on the ground and at their commanders, you don’t see any issues between the two sides. You see these videos released where they are playing tug of war and musical chairs together. It shows there’s a competition between the two entities, but it’s good-natured. You don’t see internecine fighting between the two groups at this juncture. Depending on the locale in Syria, some on the ground view [their fighters] as interchangeable, and in other areas, there’s a difference.

SD: How many foreign fighters are there now?

AZ: A conservative estimate would probably put it at 5,000, and a liberal estimate would say 10,000 foreigners, but it should be noted that in that figure is everyone who has gone to Syria since the conflict started, including those killed, returned home or arrested. Based on my own data, I’ve been able to see that at least 750 to 1,000 foreign fighters have died in Syria.

SD: People are saying it could become the global ground zero for jihad.

AZ: It already has, in some respect. The only other fight that’s seen this many foreigners is Afghanistan, when they were fighting the Soviets, and it took five to six years after the Soviet invasion for individuals to even start trickling in there to help the Afghan mujahedeen. We’ve seen these numbers in Syria in just two and a half years, and most people only started coming after January 2012, when al-Nusra announced its presence. It’s starting to become the key zone and base for jihadist groups and operations. It has a pull for so many people historically and religiously. They don’t necessarily all see this as a war about the regime or territory or governance, but as a legitimate religious war against Shiites, so some people have this visceral pull as the conflict’s gotten worse. In many respects it’s for Sunni solidarity.

Once individuals get there and get in touch with groups like al-Nusra and ISIS, they start getting socialized into the jihadi world view. Of course some who go there are already prone to this movement, but many of the foreigners who go are not.

SD: How are these groups funding themselves this far into the stalemate?

AZ: Jabhat al-Nusra has three major ways they fund themselves: ISIS provides al-Nusra with half its budget each month. The second aspect is related to private donors from the Gulf, who provide money and fighters. The third is that they’re winning spoils of war, in terms of weapons.

If they are paying their fighters, that would add up, since they have 5,000 to 10,000 fighters. You also have to think about the money they need for food and for medical supplies, as well as maintaining the weapons they have. It wouldn’t be cheap. It appears they’re able to keep it up, which means their stream of funding is not being disrupted. I’ve seen figures where fighters get anywhere from $200 to 300 per month.

ISIS also gets money from private donors, mostly in the Gulf, but they are also involved in illegal black market activities in Iraq like robbery and extortion.

SD: What are the biggest challenges for Jabhat al-Nusra and ISIS in the months ahead?

AZ: One of their biggest challenges is that there is a small element of individuals who do not like them. It’s not surprising, because of their ideology. At this point, we’ve only seen individuals at the civilian level protest against them in Aleppo and Raqqa governorates. The question is whether civilian disaffection with al-Nusra and ISIS comes to other factions that are militarized.

We’ve seen incidents of fighting between the jihadi elements and mainstream rebels, but it’s been really small and not widespread. Both of the two jihadi organizations are still very important in the fight against the regime and Hezbollah. So even though they don’t ideologically agree with them, [the more moderate opposition] will pay lip service because they know they need them.

It’s one of the biggest ironies: even though the opposition has been so fractured, they’re interconnected on the battlefield because there’s not one faction that’s strong enough to strong-arm another faction. They need each other. That’s why you sometimes see non-Islamists working with jihadists on the battlefield. Jihadists have the advantage right now because they’re the best fighters and they’ve done the best job providing security and social services in liberated areas. The question is whether they can maintain those soft power elements as well as their ability to not create problems with the local populace, which might eventually turn their backs on them.