What Happens if Syrian Troops Attack Idlib?

After recapturing most of Syria, President Bashar al-Assad is threatening to march on opposition forces in Idlib, the densely populated northwest province that shares a border with rebel ally Turkey.

But a military assault would prove very costly, and analysts say Ankara and regime ally Moscow may ultimately choose to keep Assad's troops in check.

- The last redoubt -

Idlib is the last haven for Syria's fractured armed opposition, which this year alone lost key bastions near Damascus and in the south.

The province shares a roughly 100-kilometre (60-mile) border with Turkey and fell to jihadists and rebels in 2015.

Now, around 60 percent is held by Hayat Tahrir al-Sham (HTS), led by jihadists from Al-Qaeda's former Syria affiliate.

The rest is controlled by rival Islamists and rebels, while regime forces hold a southeastern sliver.

The province forms a "de-escalation zone" agreed in 2017 by Turkey, Russia, and fellow regime ally Iran meant to prevent hostilities there.

It is the only such zone left, after Assad recaptured the other three this year.

- Why does Assad want Idlib? -

Throughout Syria's seven-year war, Assad has pledged to recapture every inch of the country. After Turkish troops intervened in 2016, Damascus regularly lambasted them as "occupiers".

Last week, Assad said Idlib, where Turkey has forces deployed, is his next priority.

Idlib's strategic importance for the regime lies at least in part in the M5 highway, which links second city Aleppo in the north to Damascus, and then south to the recently recaptured Nassib border crossing with Jordan.

The stretch in Idlib cuts through rebel territory, but Turkish and Russian monitors are positioned along it.

Assad's push for Idlib will primarily stem from his interest in the highway, says analyst Fabrice Balanche.

- How likely is an assault? -

Talk of a possible looming assault on Idlib is rife in government-held Syria, but analysts say there is cause to be cautious.

First, Russia's own Syria envoy Alexander Lavrentiev said this week there was "no question of an operation" on Idlib.

The regime's main obstacle, says Center for a New American Security analyst Nicholas Heras, is Ankara.

"The greatest impediment to the Assad government in Idlib is Turkey and the Turkish government's policy toward northwest Syria," he says.

President Recep Tayyip Erdogan is wary an assault could push thousands of people to the frontier, much like what happened along the Jordanian border in June when troops began attacking southern Syria.

"For the time being, Erdogan is pursuing an over-my-dead body policy toward Assad's potential military action in Syria," says Heras.

Nasr al-Hariri, who heads Syria's mainstream opposition, told AFP last week Turkish "guarantees" would likely bar an assault.

And Nawar Oliver of the Turkey-based Omran Centre expects Russia, Turkey, and Iran "will not allow any kind of large-scale war in the north, because that will affect everyone there".

- But, what if? -

If troops did attack Idlib, says Oliver, it would only be with the approval of all three powers.

"If the regime moved on this goal, it's probably going to be in a deal. This deal is not finalised," he says.

But that would spell catastrophe for the province's 2.5 million residents, half of them displaced from other Syrian provinces.

Idlib's population has swelled with tens of thousands of rebels and civilians transferred there en masse from other towns recaptured by the regime.

People would have nowhere to flee, UN regional humanitarian coordinator for Syria Panos Moumtzis said.

"There is no other Idlib to take them out to," Moumtzis warned earlier this year. "Really, this is the last location."

As a result, thousands if not more would rush to the border with Turkey to seek safety.

- What about HTS? -

Damascus and Moscow justify bombing Idlib by pointing to the presence of the jihadists from HTS, designated as "terrorists".

Ankara wants to prevent the two countries from using the same excuse for a ground assault, says Heras.

"The Turks are holding the line that HTS is Turkey's matter, and not an issue that Assad can use to launch a war on Idlib. But there is a time clock that is running now," says Heras.

On Wednesday, Islamist heavyweights Ahrar al-Sham and Nureddine al-Zinki merged with four other rebel factions opposed to HTS to form the National Liberation Front.

"Sooner or later, if the Turks want to stay in Europe and America's good graces, Erdogan is going to have to act more decisively against the terrorist organisations in Idlib," Heras says.

Lavrientev this week said Moscow hoped Ankara and its rebel allies would act to keep Idlib stable.

Ultimately, to avoid a regime assault, Oliver says, Turkey may wage "a military operation inside Idlib to eliminate the hardliners among HTS and other extremist groups".