US-led air strikes in Syria have killed more than 1,000 jihadists in the past three months, nearly all of them from the Islamic State group, a monitoring group said Tuesday.

"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.