BEIRUT — While the final battle to retake the Islamic State group’s last pocket of territory rages in eastern Syria, violence is escalating in the country’s northwest, pitting al-Qaida-linked militants against Syrian government forces.

The alarming violence in the Idlib region threatens to unravel a truce reached between Turkey and Russia last year that averted a bloody assault by the government to retake the province, the last major rebel stronghold in war-torn  Syria. The escalation raises fears once more of a major assault by the forces of President Bashar Assad.

Idlib has been in the hands of opposition forces for years, even as Assad’s military has succeeded in retaking other rebel enclaves one after the other. The province is now home to some 3 million people, many of them displaced from other former opposition territory.

Earlier this year, al-Qaida-linked militants took over the province, squeezing out most other factions after clashes with Turkey-backed opposition fighters.

Since then, government forces have intensified airstrikes and bombardment of Idlib towns. Since mid-February, some 100,000 people have been displaced, largely by government bombardment, and have fled to villages deeper in rebel-held territory, according to the Britain-based Syrian Observatory of Human Rights. The group said that around 140 people, including 69 civilians, have been killed.

The mounting violence points to how Syria’s nearly 8-year-long civil war still has the capability to burst once more into major bloodshed.