Both the Syrian Observatory for Human Rights and Syria's opposition said the air strikes were carried out by Russian war planes.
Survivors of one of Syria's deadliest air attacks this year have been to speaking to TRT World.
On June 7, at least 51 people were killed in air strikes on the town of Zardana, in Idlib province.
TRT World's John Joe Regan reports.
The Syrian Observatory for Human Rights said the strikes were likely carried out by Russian war planes.
"War planes, which are likely Russian, targeted the village of Zardana in northern rural Idlib and caused the highest death toll in a single attack on the region since late March," Rami Abdulrahman, the director of the Britain-based war monitor said.
However, Russia denied that its war planes carried out the air strikes.
The Russian Defence Ministry was quoted as saying it had information about fighting between Nusra Front militants and opposition fighters involving heavy artillery fire in the region.
But, Mustafa Haj Yousuf, head of the local civil defence unit, told Anadolu Agency that five members of the civil defence unit were also among those injured when the strikes targeted a market and an area near a mosque.
“The air strikes were carried out by SU-24 Russian fighter jets from Latakia airbase,” the Syrian opposition said in a statement.
Idlib, under the control of anti-regime armed groups, was declared a "de-escalation zone" during peace talks between Russia, Turkey and Iran in Astana, Kazakhstan, in May last year.
Northwestern Idlib region is the largest populated area of Syria still in the hands of groups opposed to the Damascus regime of Bashar al Assad.
In recent years, tens of thousands of fighters and civilians have fled there from parts of the country which the Syrian army has recaptured with the help of Russia and Iran.
Despite Russia's agreement that Idlib is a de-escalation zone, the Assad regime and Russian forces regularly bomb the region.