Hayat Tahrir al-Sham (HTS) is wiping out rivals and taking areas of strategic interest to Turkey and Bashar Al Assad's government in Syria's northern provinces.
Al Qaeda-linked militants in Syria are strengthening their grip on territory in western Aleppo’s rebel-held countryside, nearly 18 months after taking most of the neighbouring province of Idlib.
The Hayat Tahrir Al Sham alliance, Syria’s strongest and largest militant group, is trying to consolidate its hold on more of the rebel-held north for leverage in any talks with interested parties, including Turkey and Russia, analysts say.
“The more territory Tahrir Al Sham seizes in northern Syria, the stronger its hand will be in future negotiations,” said Nawar Oliver, a Syria specialist at the Omran Centre in Turkey. “Power comes from control of territory so they are in need of this territory.”
Turkey is the most involved player in these parts of northern Syria. It established observation posts there and supports rebels near its own southern border.
A surprise campaign by Hayat Tahrir Al Sham last week caught Turkey and allied rebels by surprise.
With thousands of rebels stationed on front lines before a planned Turkish assault on the Kurdish-held city of Manbij in north-east Aleppo province, Hayat Tahrir Al Sham seized towns and villages from the Ankara-backed National Liberation Front in the south-east.
“Tahrir Al Sham chose the right moment to attack,” Mr Oliver said.
He said concentrating its forces near Manbij left rebels in Idlib and elsewhere in Aleppo exposed.
As of Sunday evening, clashes left 61 Al Qaeda-linked militants and 58 National Liberation Front fighters dead, the Syrian Observatory for Human Rights said. Hayat Tahrir Al Sham captured large amounts of territory from its rivals.
Last week, it seized all ground previously held by the powerful Noureddine Al Zenki rebel group, which is an affiliate of the National Liberation Front, in rural Aleppo.
“Zenki had been a thorn in Tahrir Al Sham’s side and one of the most stubborn challenges to its dominance, and now it has been defeated,” said Sam Heller, a senior analyst at the International Crisis Group.
The Observatory said that hundreds of Zenki fighters and other defeated National Liberation Front affiliates retreated to territory held by Turkey-backed rebels in Afrin, which Hayat Tahrir Al Sham cut off from other territory in Idlib.
It is also establishing control over important zones that would be politically and strategically useful in talks, including areas near the M4 and M5 motorways, Mr Heller said. These roads run east to west and north to south, linking the government-held city of Aleppo with Damascus and the Mediterranean coast. Both have been cut off in Idlib since 2014.
The M5 was a major trade route that connected the commercial centre of Aleppo to the Syrian capital and on to the Jordanian border in the south. Reopening these roads would help to revive trade from Turkey, which could then go to regime-held areas and on to Jordan and the Gulf.
An agreement brokered by Turkey and Russia in Sochi in September last year to set up a demilitarised zone in Idlib also called for the two strategic routes to be reopened.
“It seems Tahrir Al Sham is positioning itself to negotiate the opening of the M4 and M5 highways,” Mr Heller said.
The Syrian government and its Russian allies repeatedly used the presence of Hayat Tahrir Al Sham in northern Syria to justify attacks on the area.
Its expanded foothold may threaten the more than 2.5 million civilians in Idlib, half of whom have been displaced from other parts of Syria.
It remains to be seen whether the group’s expansion will upend the Sochi agreement to create a demilitarised zone around Idlib. But Russia and the Syrian government resumed air strikes at the weekend.
Three civilians were killed and nine others were injured in Russian air strikes that hit Aleppo, Turkey’s state-run Anadolu news agency reported on Saturday.
Anadolu claimed that most of the casualties were in Darat Izza, a town captured by Hayat Tahrir Al Sham last week.