IS suicide car bomber kills six rivals in Syria: monitor

At least six jihadists were killed when asuicide car bomber from the rival Islamic State militant group detonated an explosive at a roadblock in Syria's northwestern province of Idlib, a monitor said.

"A jihadist in a bomb-laden car blew himself up at a roadblock controlled by HTS fighters... killing six of them," said Rami Abdel Rahman, director of the Syrian Observatory for Human Rights.

The attack on Hayat Tahrir al-Sham, which is led by Syria's former al-Qaeda branch, took place on the western outskirts of Idlib city.

IS also "executed five HTS members this weekend," Abdel Rahman told AFP.

Most of Idlib province is held by an array of Islamist and jihadist groups, with only parts controlled by the Russian-backed government.

The Islamic State group is attempting to make a comeback in the area, after being driven from vast swathes of its self-proclaimed "caliphate" last year.

In January, the terror group declared Idlib under its control, despite the province being dominated by its jihadist rivals.

Since being forced to flee their last pockets of resistance in the capital Damascus last month, IS has escalated attacks on loyalist forces in northeastern Syria.

In the past three weeks nearly 250 pro-regime fighters have been killed in such attacks, according to the Britain-based Observatory.

A major assault launched by IS on the eastern city of Albu Kamal on Friday left at least 48 regime forces and allied fighters dead, as well as 32 jihadists including 10 suicide bombers.

It took three days for the regime to oust IS from the city, which lies on the Iraqi border.

The jihadist group is estimated to control less than three percent of Syrian territory, a staggering decline after once claiming half the country.

But it continues to pose a threat to the regime in Syria, where the conflict has claimed more than 350,000 lives since 2011.

Agencies contributed to this report.