Clashes in northwest Syria kill 35 fighters: Monitor

The northwestern region has come under increasing fire by the regime and its ally Russia in recent weeks, despite a buffer zone deal intended to shield it from any government offensive.

The region controlled by Hayat Tahrir al-Sham, Syria's former Al-Qaeda affiliate, includes most of the Idlib province as well as parts of neighbouring Aleppo, Hama, and Latakia provinces.

The Syrian Observatory for Human Rights said that 16 loyalists and 19 jihadists died from Sunday to Monday in clashes in the area of Jabal al-Akrad in Latakia province, which lies on the bastion's northwestern edge.

Russian and regime aircraft bombarded the area on Monday with missiles and barrel bombs, while they also carried out strikes on southern areas of the region, said the Britain-based war monitor.

Russian air strikes hit a branch of the White Helmets rescue volunteers in the town of Kafranbel, knocking it out of action, the Observatory and a rescue worker said.

"Two high-explosive missiles hit the centre" just minutes after its personnel had headed out to the site of strikes in a nearby village, Oneida Zikra, the civil defence chief for the area, told AFP.

In a regime-held town in Hama province to the south of the bastion, retaliatory rocket fire on Monday killed one child, the Observatory and state news agency SANA said.

Five others were also wounded in the Christian-majority town of Suqaylabiyah, SANA added.

Idlib's three million inhabitants are supposed to be protected from a massive regime assault by a September buffer zone deal signed by Russia and rebel backer Turkey.

But that agreement was never fully implemented after jihadists refused to withdraw from the planned buffer area.

An uptick in air strikes and shelling displaced 180,000 people between April 29 and May 9 alone, the United Nations says.

The Observatory says 119 civilians have been killed in the bombardment since late April.

In a filmed interview released on Sunday night, HTS chief Abu Mohammad al-Jolani urged supporters to "take up weapons" to defend Idlib.

The spike in violence signalled "the death of all previous agreements and conferences", he said.

Damascus has not announced a wide offensive, but instead regularly announces targeting "terrorist" -- meaning jihadist or rebel -- positions.

Analysts believe the offensive will be limited.

The civil war in Syria has killed more than 370,000 people and displaced millions since it started with the brutal repression of anti-government protests in 2011.