Several hard-line rebel groups have launched a new offensive in northwestern Syria, less than a month after seizing control of the provincial capital.

The conservative Islamic opposition factions, including the al-Qaida-affiliated Nusra Front, are coordinating the multi-pronged campaign whose primary target appears to be Jisr al-Shughour in Idlib province.

Opposition fighters are also attacking government checkpoints in a plain south of the town and nearby military facilities.

The Islamic rebel groups taking part in the operation posted a statement online late Wednesday announcing the start of the offensive, which they call "Battle of Victory."

The Britain-based Syrian Observatory for Human Rights said Thursday the rebels have taken five checkpoints since the offensive began, including two near Jisr al-Shugour.

The new offensive comes some three weeks after rebels captured Idlib city.