Russia denounced accusations on Wednesday that its air strikes in Syria have targeted civilian areas, despite reports that about one-third of all those killed in such attacks were non-combatants.

"All of these anonymous and unsubstantiated statements about the alleged use of Russian aircraft on civilian targets in Syria is increasingly reminiscent of hypnotists' acts in travelling circuses," Russia's defence ministry said in a statement, calling the claims "absurd".

Moscow has come under growing criticism from Syrian activists, international human rights groups, and the West for allegedly attacking medical facilities, schools, markets and residential areas during its three-month bombing campaign in support of the government of President Bashar al-Assad against opposition fighters.

The US State Department said on Tuesday that Russian air strikes have killed "hundreds".

The Syrian Observatory for Human Rights, a UK-based monitoring group, said on Wednesday at least 792 civilians - including 180 children - were among 2,371 killed by Russian air raids since September 30.

The rest of the dead were fighters from the Islamic State of Iraq and the Levant group, as well as Syrian opposition groups, according to the observatory.

Last week Amnesty International, the UK-based rights group, issued a report saying Russian raids violated international law and could constitute war crimes.

Russia's defence ministry spokesman Igor Konashenkov had dismissed the report, saying it was made up of "cliches and fakes".

Source: Al Jazeera and agencies