Idlib is dominated by an alliance led by Syria’s former al-Qaeda affiliate, the Hay’et Tahrir al-Sham armed group.

A double bomb attack on Monday in Syria’s northwestern city of Idlib killed at least 15 people, including four children, a war monitor reported. Dozens of others were wounded.

The first blast was caused by an explosive device planted under a car in Qusour neighbourhood during rush hour, the UK-based Syrian Observatory for Human Rights said.

A motorcycle bomb then detonated after ambulances arrived at the scene of the first blast, said the group, which relies on a network of sources based in Syria for its information.

There was no immediate claim of responsibility for the attack which the Syrian Observatory said also wounded at least 50 others.

The Local Coordination Committees and the Syrian Civil Defence, a group of first responders, also reported casualties.

The city has been hit by a series of bombings in recent months that have killed or wounded scores of people.

The Observatory and Civil Defence earlier reported government shelling of rebel-held towns south of Idlib, saying several people were wounded.

‘Salvation Government’

Idlib, the last major part of Syria still outside the control of President Bashar al-Assad’s government, is dominated by an alliance led by Syria’s former al-Qaeda affiliate, Hay’et Tahrir al-Sham (HTS).

The group took administrative control of the entire region last month after overpowering smaller Turkey-backed rebel factions.

Islamic State of Iraq and the Levant (ISIL, ISIS) also has sleeper cells in Idlib.

A local office of the “Salvation Government”, an administrative body created by HTS, is located on the street targeted in Monday’s attack.

Four HTS fighters were killed in the blast, the Syrian Observatory said.

Idlib has been protected from a planned Syrian government ground attack – backed by air power from its Russian ally – since September by a buffer-zone deal agreed among Damascus, Moscow, and Ankara.

Nearly eight years into the devastating war that has killed hundreds of thousands of people, the Syrian government controls nearly two-thirds of the country.