"At least 1,171 have been killed in the Arab and international air strikes (since September 23), including 1,119 jihadists of the Islamic State group and Al-Nusra Front," said the Syrian Observatory for Human Rights, which relies on a network of activists and medics across the war-ravaged country for its information.
Among those killed were 1,046 members of the IS group, which has seized large chunks of Iraq and Syria and is the main target of the US-led air strikes.
The remaining 52 were civilians.
IS has declared a "caliphate" in the parts of Iraq and Syria that it has overrun, and its militants have been accused of widespread atrocities, including beheading Western hostages.