The shelling targeted residential neighbourhoods in the city of Jisr Al Shughur, west of Idlib, this morning, the White Helmets said on X, formerly Twitter.
No casualties were reported from the attack, it said. The town on the border of the governorate, known for its semi-rural setting and olive groves, has been a hotbed of anti-government resistance for decades, and a site of frequent fighting during the main period of the country's civil war, between 2011 and 2018.
The shelling and rocket attacks follow a drone strike on a military college in Homs that killed at least 112 people, one of the worst attacks on regime forces in many years.
The White Helmets reported that three children from the same family were injured on Friday in Russian air strikes on the village of Jiftlik Haj Hamoud in the western countryside of Idlib.
An elderly woman and four of her children were killed on Thursday in shelling by the Syrian army in the war-torn country's north-west.
Thursday's bombardment hit their house in Kfar Nuran, close to the front line in the last rebel stronghold in the western province of Aleppo.
Parts of Idlib province and areas bordering the provinces of Aleppo, Hama and Latakia are controlled by Hayat Tahrir Al Sham, led by Al Qaeda's former Syria branch.
A ceasefire brokered by Russia and Turkey was declared in Idlib after a government offensive in March 2020, but it has repeatedly been broken.
The civil war started at the end of 2011 after the authorities violently crushed a peaceful protest movement against Mr Al Assad, who has ruled since 2000.
Strikes on the north-west by the army and Russia, President Bashar Al Assad's most powerful ally in the civil war, have increased in recent months as the armed opposition consolidated its grip on the area.