DAMASCUS, Aug. 4 (Xinhua) -- Lawlessness is on the rise in the main rebel stronghold in the northwestern province of Idlib amid explosions and assassinations, a war monitor reported on Saturday.

The rebels of the Levant Liberation Committee (LLC), also known as the al-Qaida-linked Nusra Front, are on alert in Idlib as prisoners with the Islamic State (IS) militants escaped the central prison of Idlib run by the LLC, according to the Syrian Observatory for Human Rights.

Some of the fugitives were IS commanders, said the observatory, adding that several explosions have rocked Idlib and increased the state of lawlessness and tension among various rebel groups.

Two roadside bombs exploded in the countryside of Idlib on Saturday, leaving property losses, said the Britain-based watchdog group.

It added that an explosion rocked a big checkpoint manned by the LLC militants in the town of Sarmin in the countryside of Idlib, causing injuries and damages.

Sarmin has witnessed one of the major security operations by the LLC, whose fighters went on house-to-house raids in search of IS sleeper cells, rounding up tens of people, which raised the ire of the locals there, according to the observatory.

The observatory said the 265 rebels and others have been killed since April in the countryside of Idlib, and the countryside of the nearby Hama and Aleppo provinces.

Some 52 civilians, including eight children and five women, were among those killed in the explosions of roadside bombs and shootings.

Idlib has become the main destination for all militant groups, which evacuated areas around Damascus and other key Syrian areas after reaching deals with the army when they got fully besieged.

After the army almost dislodged the rebels from the southern region and the countryside of the capital Damascus, Idlib has become the main stronghold of various rebel groups.

The striking force in that province is Nusra Front, which is the backbone of the LLC.

The population in Idlib is estimated at over 1.5 million, with tens of thousands of rebels and their families resettling there after relocating from the provinces of Hama, Homs, and the countryside of Damascus in recent months.