The death toll of Russian air strikes in Syria's Idlib province has nearly reached 100, as several dozen of those who were critically injured in the attacks on Saturday have died, a volunteer rescue group reports.

"After 32 hours of our rescue operation, and following the deaths of those who were critically injured, the total death toll of the strikes has risen to 96," the Syria Civil Defense said in a press release on Sunday.

The United Kingdom-based Syrian Observatory for Human Rights put the death toll at 81.

In Douma, located in Damascus' suburbs, Russian air strikes killed at least eight people on Sunday, the Syrian Observatory reported, adding that the death toll was expected to rise.

Idlib province is mostly controlled by the Fatah Army coalition - which includes al-Nusra Front, Jund al-Aqsa, Jaish al-Sunna, Liwa al-Haqq, Ajnad al-Sham, and several other factions.

The main opposition bloc, the Syrian National Coalition, said in a report released on Saturday that it had documented the deaths of 1,730 civilians due to Russian air strikes since their launch in September 2015.

At least 135 children were among those killed, the coalition said, adding that over 29 hospitals were destroyed in the strikes, in addition to schools, homes and places of worship.

In a statement, the coalition called on the UN Security Council "to assume its responsibilities towards Russians' continued violation of international and humanitarian laws".

The statement also said that "Russia's claim of fighting terrorism is a pretext to justify its aggression on Syria, which was clear from day one when its air force committed massacres against civilians.

"Nearly 94 percent of the 12,000 sorties the Russian air force has so far flown in Syria targeted civilians and the Free Syrian Army."

PHOTO CAPTION

Residents look for survivors in a site hit by what activists said were airstrikes carried out by the Russian air force in the opposition-controlled area of Maaret al-Numan town in Idlib province, Syria January 9, 2016.

Al-Jazeera