Former al-Qaeda affiliate HTS takes control of Syria's final rebel bastion of Idlib

Jihadists on Sunday took full control of Idlib province in Syria after rival rebels withdrew, strengthening their grip over the northwestern city, one of the last beyond regime control.

At the same time a car bomb exploded in Idlib killing 11 people, nine of them jihadists, the Britain-based Syrian Observatory for Human Rights monitoring group said.

The latest developments come after the jihadist group Hayat Tahrir al-Sham [HTS], which is dominated by a former al-Qaeda affiliate, agreed to a ceasefire on Friday with Ahrar al-Sham rebels.

The truce ended a week of fierce fighting between HTS and Ahrar al-Sham, which is backed by Turkey and some Gulf countries, that killed at least 92 people including 15 civilians, the Observatory said.

Analysts have said growing tensions over the past two months have been exacerbated by HTS fears of a plan to expel the internationally designated "terror" group from the province.

"Ahrar al-Sham withdrew from the city of Idlib which is now under the control of Hayat Tahrir al-Sham," Observatory head Rami Abdel Rahman told AFP.

"Hundreds of rebels left the city aboard dozens of vehicles heading towards southern Idlib province," he said.

Abdel Rahman said the HTS set up checkpoints across the northwestern city.

The fall of the city and provincial capital is symbolic.

It comes after the jihadists captured in a bloodless takeover "more than 31 towns and villages" across Idlib province over the past two days, the monitor said.

The HTS is dominated by the Fateh al-Sham faction, which was previously known as al-Nusra Front before renouncing its ties to al-Qaeda.

The HTS and Ahrar al-Sham were once allies and fought alongside each other to capture most of Idlib province from Syrian government forces in 2015.

The truce they agreed to on Friday calls for the release by both sides of prisoners and the "withdrawal of armed groups from the Bab al-Hawa" border crossing with Turkey.

Bab al-Hawa, which had been controlled by Ahrar al-Sham, would be handed over to civilian administration, it said.

Abdel Rahman said the presence of Ahrar al-Sham rebels has been greatly diminished in Idlib province, which they once dominated. Rebels were left only in Ariha town and part of Jabal al-Zawiya in the southeast.

Syria's conflict erupted in mid-March 2011 with peaceful anti-government protests that were brutally repressed by the government.

It quickly evolved into a war involving local, regional and international players on a multitude of fronts, that has killed more than 330,00 people and displaced millions from their homes.

Russia plans to establish a new "de-escalation zone" in the Syrian province of Idlib, Russian news agencies cited the Russian Defence Ministry as saying on Monday.