A week of clashes between al-Qaeda militants and a number of opposition militias in several parts of Syria has claimed the lives of 500 fighters and civilians.
The ultra-extremist Islamic State of Iraq and the Levant (ISIL) mounted attacks against a number of villages and towns in rural Aleppo and Idlib in the northwest, after the al-Qaeda-inspired group was chased from its positions in the city of Aleppo earlier this week.
The opposition observatory said that clashes between opposition militias and ISIL militants took place near the towns of Al-Bab, Tal Rifaat, Bazaa, Qabbasin, Kfar Halab and Sheikh Ali, all in the province of Aleppo.
The Observatory said fighting was taking place on the outskirts of these areas, however, indicating that mainstream and Islamist militants have regained their positions and are defending themselves against counterattacks by ISIL militants.
In the town of Anadan, the Observatory said that 20 fighters from the opposition militant battalions were killed, without indicating the casualty figure in the ranks of ISIL. Fighting also raged in rural areas of the province of Idlib.
The ISIL militants have largely fallen back to the province of Raqqa further east, and the Observatory said fierce fighting took place in the city and the border town of Tal Abyad. ISIL militants managed to take control of two neighborhoods in but was never under the sole control of ISIL.
The militant group shared power with other militias, which are now waging the offensive against it after the behavior of ISIL militants alienated large sections of the population in militant-held areas by enforcing ultra-conservative Islamic rule.
Opposition militants in the city of Tabqa on the Euphrates posted a video which they claim shows a dismantled car bomb that was going to be used by ISIL fighters. The Observatory said ISIL has resorted to car bomb attacks periodically throughout the weeklong offensive against it.
However, even the slogan for the nationwide weekly protests reflected some of the tensions that have been generated by the campaign against ISIL. Some activists on social media circulated images proclaiming a "day of rage against al-Qaeda" .
In the Bustan al-Qasr neighborhood of Aleppo, people chanted "azadi, huriyeh", the Kurdish and Arabic words for freedom, as well as "the people want the execution of ISIL".
Separately, the White House said that it was still reviewing how to resume shipments of nonlethal aid to moderate militant groups after an incident last month where Islamist fighters seized supplies from a warehouse near the Turkish border.
White House spokesman "Jay Carney" told reporters at a briefing "No decisions have been made yet regarding the resumption of nonlethal assistance to the Free Army, but we have resumed deliveries of nonlethal assistance into northern Syria to civilian actors".