The warplanes hit near a school in opposition-held Saraqib district of the province, a war monitor and a rescue group say. The dead include 16 children. Meanwhile, an opposition group has agreed to evacuate a town in besieged eastern Ghouta.
Russian air strikes killed at least 20 civilians in the opposition-held Saraqib district of Syria's Idlib province on Wednesday, a war monitor and a rescue group said.
Mustafa Haj Yusuf, director of the White Helmets civil defence group, told Anadolu Agency that at least 16 children had been among the casualties.
According to the Britain-based monitor Syrian Observatory for Human Rights (SOHR), "Twenty civilians, including 16 children, were killed in an air strike that hit near a school in Idlib province."
According to opposition sources, Russian warplanes took off from the Hmeymim air base in Syria's Latakia province, from which they conducted several air strikes in and around the Saraqib district.
In the last 11 days, at least 56 people have been killed by air strikes in opposition-held parts of Idlib and Hama provinces.
Eastern Ghouta evacuation deal reached
Meanwhile, in the besieged eastern Ghouta, an opposition group has agreed to evacuate a town it controlled, the first such deal in the last opposition bastion near the capital Damascus.
Members of Ahrar al Sham, which holds Harasta, agreed to lay down arms in return for safe passage to opposition-held northwestern Syria and a regime pardon for people who wished to stay, the opposition sources said.
Some 1,500 opposition forces and 6,000 of their family members will be transported to opposition-held Idlib province in two batches starting on Thursday.
Russia's defence ministry, which the opposition sources said had brokered the deal, said on Wednesday it had opened a new "humanitarian corridor" near Harasta but did not indicate whether this would be part of any opposition pullout deal.
At 10:07 today 21 Mar 18 a Russian Su34 aircraft dropped a bomb on a school in Kafr Batikh (near Saraqueb, Idlib). The children evacuated to a nearby underground shelter which was bombed in a second strike minutes later. 16 children were killed, together with 3 women and 1 man. pic.twitter.com/4XgNLA297K— The White Helmets (@SyriaCivilDef) March 21, 2018
Siege and bombardment tactics
The Syrian regime has recaptured 70 percent of the territory that was under opposition control, and after weeks of bombardment forcing residents to flee.
Beside Harasta, the opposition groups still hold two other pockets in the enclave outside Damascus – the major town of Douma and an area to the south that includes the towns of Jobar, Ein Terma and Arbin.
The regime army assault, backed by Russian fighter jets, began last month.
It has killed more than 1,500 people as air strikes pound residential areas where thousands had sheltered in basements across the densely populated enclave, according to SOHR.
The regime army and its allies have for years employed siege and bombardment tactics to force opposition groups to surrender, helping Assad recover Aleppo, Homs and other areas.
The Harasta evacuation will begin with injured civilians, said one official familiar with talks.
More than 100 civilians were killed in the last two days of air strikes in eastern Ghouta with most of the raids on Douma city, the largest population centre, where more than 150,000 people still live.
Opposition groups and residents say napalm and incendiary weapons, which Damascus and Moscow deny using, were dropped on several civilian areas to force opposition groups to surrender.
Fate of Aleppo
Securing Harasta, near the closed Damascus-Homs highway, will allow the regime army to make further gains in the remaining parts of the enclave in opposition hands.
The Harasta deal may add pressure on the two main opposition groups – Failaq al Rahman in the southern pocket and Jaish al Islam in Douma – to also reach an understanding.
They have so far refused to leave the enclave, but the most likely outcome was still their transfer to opposition-held areas in northern and southern Syria, an opposition official said.
Defeat in eastern Ghouta would mark the worst setback for the opposition groups since they were driven from eastern Aleppo in late 2016 after a similar campaign of siege, bombing, ground assault and the promise of safe passage out.
Syria remains locked in a devastating conflict that began in 2011 when the Assad regime cracked down on demonstrators with unexpected ferocity.
According to UN officials, hundreds of thousands of people have been killed in the conflict to date.