The UN is "deeply concerned" about over increasing hostilities in northwestern Syria in recent months.
Farhan Haq, spokesman for UN Secretary-General Antonio Guterres, said at a news conference on Wednesday that hostilities are affecting civilians.
He said artillery shelling in Idlib left one civilian dead and four injured on Tuesday.
"Artillery shelling was also reported in other parts of Idlib and in Western Aleppo. Today, several civilian casualties have been reported following artillery shelling in Ariha town, south of the city of Idlib," said Haq.
Surge in violence
The recent escalation is the most significant increase in hostilities in northwest Syria since a ceasefire agreement in March 2020.
"The UN condemns all violence in Syria. We remind all parties to the conflict to respect international humanitarian law, including the prohibition of indiscriminate attacks and the obligation to take all feasible precautions to avoid and minimize harm to civilians and civilian infrastructure," he added.
Syria has been ravaged by a civil war since early 2011 when the Assad regime cracked down on pro-democracy protesters.
Idlib falls within a de-escalation zone forged under an agreement between Turkey and Russia.
The area has been the subject of multiple ceasefire understandings, which have frequently been violated by the Syrian regime and its allies.