U.S.-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, Dec 23, according to AFP.

"At least 1,171 have been killed in the Arab and international air strikes (since Sept 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 U.S.-led air strikes.

Seventy-two of those killed were members of al Qaeda's branch in Syria, the Al-Nusra Front, while another was a jihadist prisoner whose affiliation was unknown, the Observatory said in a statement.

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.