Unlike in neighboring Hassakeh province and in Raqqa, ISIS is losing ground to al-Nusra, largely due to the latter’s superior organization and governance tactics in Deir Ezzor. There, ISIS has failed to maintain the bases and headquarters necessary to wage a proper battle.

We asked Aymenn al-Tamimi, Shillman-Ginsberg fellow at the Middle East Centre in London, to weigh in.

Syria Deeply: What’s the situation on the ground right now in the province?

Aymenn al-Tamimi: Infighting between ISIS and other rebel groups has broken out – there’s been hints of it since breakouts first began in other provinces, notably Raqqa. ISIS has [been forced to use] suicide car bombs in Mayadeen, a town in Deir Ezzor province.

Then this month, there was wider infighting throughout the province and sides were taken – ISIS versus Jabhat al-Nusra and all the other rebel fighting factions, including those from the Islamic Front and the Free Syrian Army. It resulted in losses for ISIS – they were expelled from the town of Muhessen, which was a base for them. They also lost their base in Mayadeen.

SD: How powerful was ISIS in Deir Ezzor to begin with?

AT: Some of the news in the mainstream media has been exaggerated – often you’d see that ISIS controlled the provincial border town of Abu Qamal, which is on the border with Iraq. But it has never been under ISIS’s control. They had a presence in the surrounding areas, and they briefly established a base in the town itself in May, but then in June, control switched back to al-Nusra.

Abu Qamal has six different active factions and al-Nusra is the most influential because they have control over its local Sharia committee. On the whole, ISIS has lost ground in Deir Ezzor because al-Nusra has established the most overall influence in the province. If you look at Hasskeh, just to the north of Deir Ezzor, you’ll see ISIS has done much better and gained ground against [IF battalion] Ahrar al-Sham and al-Nusra. There’s a battle going on in the Hassakeh town of Markadeh, which ISIS controls as a stronghold, and there they have so far withstood both al-Nusra and Islamic Front reinforcements.

The overall picture is that each side is now focusing on consolidating where it’s been stronger all along: ISIS is stronger in Raqqa and Hassakeh, and al-Nusra is stronger in Deir Ezzor.

SD: So why is al-Nusra more influential than ISIS in Deir Ezzor, to begin with?

AT: It’s the same thing that comes back to Idlib, where it lost lots of ground because it never had many strongholds – in most towns and cities, they were just one of many rebel factions. I don’t know of any actual ISIS strongholds in Deir Ezzor. Here they were always [relegated] to being one of many factions, and they were competing with al-Nusra and the IF for control of the province’s oil and gas reserves.

You’d think they would have more control in Deir Ezzor, because it’s so close to the Iraqi border. But one major reason is that al-Nusra is more of a pragmatic group when it comes to working with others. They’ve built particularly strong links with the tribes of Deir Ezzor province. They have good working relations with other groups, and they’ve been able to gain control of Sharia committees in the province. And they’re the most influential in Abu Qamal because they have control of the Sharia committee there too.

Nusra has made a very good start of building its influence in the province – Abu Qamal has an al-Nusra welcome sign. They have been very pragmatic, have built up tribal support, have had a long monopoly over oil and gas resources, and spearheaded most rebel offenses in the province. ISIS wasn’t able to [match] it, though they enjoyed some popularity back in May and June, and there were some defections then from al-Nusra to ISIS. But when [al-Qaida chief Ayman al-Zawahiri] issued his directive, [the goodwill] switched back from ISIS to al-Nusra. Since his official disavowal, al-Nusra no longer has a reason not to push back against ISIS.

The ISIS influence is strong in Hassakeh right now, and there is a particularly strong border link with Iraq there. ISIS [fighters] cross from Nineveh province in Iraq, so there’s a strong interchange and traditionally less al-Nusra influence. [But] when you look at all these things, it’s not surprising that al-Nusra is the most influential here, despite the proximity to Iraq.

SD: How much focus will ISIS put on Deir Ezzor in the month ahead? How many resources?

AT: They’re going to focus more on on consolidating their position in what they already have. Rather than stretching all the way from Anbar [in Iraq] to Deir Ezzor, as is often reported, I’d say Deir Ezzor is really a cut-off to the ISIS sphere of influence. You have to go to the north if you want to follow the stretch of ISIS influence from Iraq into Syria, rather than the traditional media conception, which is that ISIS influence in Syria runs from the Euphrates River over through Deir Ezzor.