Five children were killed during heavy shelling on a Christian town in Syria this week. 

The children were aged six to 10 and had been playing near a monastery at the time, the Syrian Observatory for Human Rights (SOHR) reports. 

A 35-year-old woman was also killed in a separate rock attack a few streets away.

The assault on the town, which is held by Syrian government forces, has been blamed by state media SANA on rebels affiliated with al-Qaeda.

Local priest Maher Haddad told the Associated P: "The kids went out to play after some days of calm."

SANA said the Syrian army had retaliated by firing shells towards rebel positions along the southern edge of Idlib, the last rebel-held province in Syria.

Hayat Tahrir al-Sham, formerly a part of al-Qaeda, is the dominant group in the region and, according to locals, has sought to confiscate the property of Christians.

SOHR said the area had seen a dramatic escalation in violence in the past month in which around 300 people have died.

Claire Evans, Regional Manager for the Middle East at International Christian Concern, said Christians were caught between both sides of the conflict. 

"The Syrian Civil War is a sad example of the indiscriminate killing of civilians and senseless violence," she said.

"As the situation escalates in Idlib, many have warned that an increase of targeted massacres would be the result. It has started—with Christians paying a high cost as they are often viewed as vulnerable, second-class citizens.

"Their villages have become a pawn in a greater strategy for the multiple factions involved in the civil war. We must keep the families of the deceased in our prayers, and offer up continued prayers for the safety of those believers who find themselves caught between Syria's warring sides."