The militant group Hayat Tahrir al-Sham (HTS) is now in control of Idlib province and the neighbouring Aleppo countryside, following days of fierce fighting with the Turkish-backed National Liberation Front—a coalition of rebel groups in the northwest. Largely abandoned by Turkey, the Front has agreed to sign over all its territories to HTS, a former affiliate of Al Qaeda.

HTS launched an offensive on northwest Syria on New Year’s Day, taking dozens of towns and villages from the National Liberation Front. Though Russia launched airstrikes on Idlib and Aleppo provinces on 4 January, they seemed more to target civilians than HTS, hitting residential areas and killing two civilians. Turkey, a key player in the region, didn’t respond to the group’s provocations. The next day, the militants seized Al Atareb town in Aleppo, which is home to 60,000 people.

As fighting continued, HTS advanced on the important city of Maarat al-Numan, home to more than 80,000 people. Though residents bravely demonstrated against the group, there were fears HTS could take the city. The deal with the National Liberation Front has prevented an attack on Maarat al-Numan but created other problems for its residents and people across the region.

“HTS’ governance will result in increased human rights abuses and further deterioration in the humanitarian situation, and this situation will be used as an excuse by the Assad regime and Russia to launch an offensive to retake Idlib,” says Kenan Rahmani, advocacy manager at The Syria Campaign. “Turkey and the US must stop ignoring the situation in Idlib; together they must restore support to civil society initiatives, and take serious steps to ensure moderate democratic governance prevails over HTS.”

Isam Khatib, director of the civil society organisation Kesh Malek, which operates in northwest Syria agrees. “The international community must take responsibility for the more than three million civilians in the northwest,” he says. “They must be protected and real efforts taken to reach a political solution.”

For now, neither Turkey nor the US have showed inclination to act in northwest Syria. As HTS prepares to take over Idlib and Aleppo countryside, the National Liberation Front will begin evacuating thousands of its fighters to nearby Afrin, removing military opposition to the group. But with the fighting having violated the Russian-backed Idlib demilitarised zone, it remains to be seen how Moscow and the Assad regime will respond.