Six more civilians were killed in Idlib's de-escalation zone Friday as violence continues to escalate in the region.

The planes that conducted the attacks reportedly belonged to the Russian military and attacked several towns and villages in the region early in the morning.

The Sochi agreement was reached in September between Ankara and Moscow, envisaging the preservation of the cease-fire in Idlib, with the withdrawal of heavy arms and radical groups from the region.

Idlib, the last opposition enclave in Syria, had a prewar population of 1.5 million, which swelled to around 3 million with new refugee waves after it was designated a de-escalation zone under the Astana agreement between Turkey, Russia and Iran in May 2017 to pave the way for a permanent political solution in Syria.

The Assad regime's attacks on Idlib are also prompting fears of a new refugee wave, as international organizations warn of a looming humanitarian crisis.