Some 3,300 people have been killed in fighting between rebels seeking President Bashar al-Assad's ouster and their erstwhile jihadist allies since clashes erupted in January, a monitoring group said Wednesday. "Some 3,300 people have been killed ever since the start of fighting on January 3 between the (jihadist) Islamic State of Iraq and the Levant (ISIL) on one side, and (rebel) Islamist and other groups on the other," said the Syrian Observatory for Human Rights.