Forty five people were killed and many others were wounded on Wednesday, as Syrian army forces conducted series of attacks in the northern Syrian cities of Aleppo and Raqqa, local sources say.

15 people were killed in Tariq al-Bab district of Aleppo, where the oppostion holds control, after Syrian army forces conducted barrel bomb attacks.

30 of those killed were in Raqqa, which is under the Islamic State of Iraq and the Levant (ISIL)'s control, Syrian Revolution General Commission (SRGC) said in a stament.

Syria has been gripped by almost constant fighting since the regime launched a violent crackdown in response to anti-government protests in March 2011, triggering a conflict, which has spiraled into a civil war.

The UN has stopped updating its death toll for the country because an official count had become too difficult to verify. At least 100,000 deaths were recorded in the last official count in July 2013.