"The raids, probably Russian, targeted former regime positions now held by the Army of Conquest," said Observatory chief Rami Abdel Rahman.
The Army of Conquest is a coalition that includes Al-Qaeda's Syrian affiliate Al-Nusra Front and Islamist groups such as its ally Ahrar al-Sham.
"Dozens of people, mostly civilians, were wounded" in the raids, Abdel Rahman added.
Russia began a wave of air strikes on September 30 targeting the Islamic State group and what Moscow calls "terrorist" organisations.
More From This Section
Elsewhere in Syria, pro-regime forces today seized a strategic rebel stronghold in the northern province of Aleppo, the Observatory and Syrian media reported.
"The army and loyalist forces now control Khan Tuman and surrounding farms in Aleppo province," the official SANA news agency reported.
State television also reported the news, saying: "Khan Tuman and the farms near it are the most important bastion of the terrorist organisations in southwest Aleppo province."
Khan Tuman was the scene of fierce clashes between loyalist forces, including fighters of Lebanon's Shiite militia Hezbollah, and Islamist rebels, said the Observatory.
The Britain-based monitoring group said 16 Islamists were killed but it did not have details of casualties on the government side.
In March, insurgents seized arms depots in Khan Tuman after several days of fighting.
Since mid-October, with air support from the Russians, Syrian forces have recaptured several areas in the north from Islamist forces including Al-Nusra Front.