Eight men from rebel groups were executed and crucified near Aleppo in northern Syria by  members of militant group, the Islamic State in Iraq and the Levant (ISIL), the Syrian Observatory for Human Rights said Sunday.

Those crucified were said to be rebels fighting against both President Bashar al-Assad and Islamic extremists like ISIL. They were shot dead before crucification, The SOHR said the dead bodies will remain on display for three days, reports The Times.

"Another man was also crucified alive for eight hours by Isis in a public centre in the city of Al Bab on charges of false testimony," SOHR wrote in a statement. The man survived the ordeal, SOHR added.

According to the Observatory, the men were accused of joining the 'Awakening Movements' that are supported by the United States.

In the east of Damascus, "fierce clashes broke out early Sunday between rebels from the Army of Islam and ISIS near the town of Hammuriyeh", the Observatory said.

Nearly 7,000 people have been killed in Syria in the militant uprising since January, reports Reuters.

The civil war in Syria, which began as a protest movement in March 2011 seeking political change,  turned brutal following Assad's crackdown. At least 162,000 people have been killed and millions displaced in more than three years of conflict in Syria and the insurgency has attracted militants and terrorists of various hues who have spread to neighboring regions.

The militants have also taken over certain areas in Iraq. Thousands of troops with tanks and fighter jets in the war-stricken country have launched a massive counteroffensive against ISIL, an offshoot of al Qaeda. The radical group is notorious for its brutality and indiscriminate attacks.