A fighter linked to an al-Qaeda group in front of the governorate building in Idlib province in 2015. (Uncredited/AP)

Islamic State-linked militants in western Syria have executed scores of rebel fighters as part of an intensifying battle with what remains of the country’s armed opposition, a monitoring group said.

The militants, an offshoot of the Jund al-Aqsa group, killed more than 150 rebels in the village of Khan Sheikhoun in Idlib province, the SITE Intelligence Group reported Wednesday.

Citing an al-Qaeda-linked news outlet, it said most of the purported victims were part of the U.S.-backed Jaish al-Nasr group.

The news could not be independently verified, although a spokesman for Jaish al-Nasr said 71 of its fighters were recently detained in the neighboring Hama province. 

As a nationwide cease-fire halts the fighting between rebels and forces loyal to President Bashar al-Assad across much of Syria, the armed opposition has descended into infighting. 

In Idlib, many have divided into two broad alliances, with smaller groups hoping that the larger ones will protect them from the other side.

One of these is Tahrir al-Sham, formed last month from a merger of Syria’s former branch of al-Qaeda, along with several other Islamist groups. The group has turned on more-moderate factions whose representatives have agreed to join peace talks with the Syrian government.

Tahrir al-Sham and Jund al-Aqsa have clashed repeatedly in recent weeks as the jihadist factions vie for influence across northwest Syria.

Meanwhile, the Syrian Observatory for Human Rights, a Britain-based monitoring network, said Thursday that the Syrian government had dropped barrel bombs on the Idlib town of Habeet. A video circulating on social media showed the apparent aftermath: a young boy sitting on the ground and crying out for his father. “Pick me up, baba, pick me up,” he shouted. The child’s legs had been blown off.

Two months after Assad’s forces recaptured the northern city of Aleppo in a battle that killed hundreds of civilians in its final weeks, human rights groups fear that Idlib could face a similar onslaught before the war is over.