The death toll from airstrikes carried out by Russian and Syrian regime forces Monday morning in the de-escalation zone in Idlib province rose to 50 civilians, according to the White Helmets civil defense agency.

Russian jets struck a marketplace in the city of Maarat Al-Numan in northern Idlib, killing 39 civilians, including a White Helmets volunteer, sources from the civil defense agency told Anadolu Agency.

Assad regime warplanes, meanwhile, struck a marketplace in Saraqib in rural Idlib, local sources in the field told Anadolu Agency. The regime airstrike left at least seven civilians dead and dozens of others wounded, they added.

According to an Anadolu Agency correspondent, Russian and regime warplanes also carried out attacks on the town of Bidama and the villages of Talmenes and Al-Kabina, killing four civilians.

The Russian Defense Ministry, however, denied that its forces had targeted any marketplace, saying Russian warplanes had not carried out any missions in the area.

Monday's deaths bring the toll to 67 in the past two days, as 17 civilians were killed in Russian airstrikes in the same de-escalation zone on Sunday.

Turkey and Russia agreed last September to turn Idlib into a de-escalation zone in which acts of aggression are expressly prohibited.

The Syrian regime, however, has consistently broken the terms of the cease-fire, launching frequent attacks inside the de-escalation zone.

Syria has only just begun to emerge from a devastating conflict that began in early 2011 when the Bashar al-Assad regime cracked down on demonstrators with unexpected severity. (Anadolu Agency)