With ISIS nearly dead in Syria, guess who’s making a comeback

Al-Qaeda's Syrian affiliate is consolidating territory in a major clash with a rival rebel group and could make the terror group a more formidable threat in the longer term than the Islamic State, US-based intelligence advisory firm The Soufan Group warns.

The warning comes amid a major clash between al-Qaeda affiliate, Hayat Tahrir al-Sham, and another Islamist rebel group in the province that the Syrian regime and its allies do not largely control. The US, by and large, is focused on defeating ISIS in other areas of Syria and has largely given over a leadership role for post-ISIS Syria to Russia, Iran, and the Syrian regime.

"The prospect of a sustained de facto governing presence by al-Qaeda in Idlib is a grave national security concern," The Soufan Group noted. "The prospect may lead to US airstrikes, though the air space over Idlib is far more complicated and crowded than over Raqqa. Idlib is just to the east of Latakia, an Assad regime stronghold with a sizable Russian military presence," the group added.

US-backed, anti-ISIS fighters have retaken approximately 40 percent of ISIS's capital of Raqqa, but continue to have a long and grueling fight ahead of them. The fight consumes the majority of US resources in Syria.

HTS and the Islamist rebel group have now struck a tenuous truce giving HTS control of the city of Idlib. The terrorist group has changed its name several times and falsely declared to cut ties with the global al-Qaeda network in order to court less extreme opposition groups on the ground in Syria.

Experts fear the terrorist group will deepen its roots in Syria and may able to launch external terror plots against the West using its new sanctuary.

"The battle against the Islamic State in Raqqa is not to be the most consequential ongoing fight in Syria," The Soufan Group lamented.