BEIRUT — Fierce clashes and air raids on Monday across northern Syria, mainly in the contested city of Aleppo, killed at least 26 people and left scores wounded, according to reports.

Syrian state media and opposition monitoring groups said insurgents bombarded government-held neighborhoods in Aleppo, killing eight people there and wounding dozens. Later in the day, activists said a government airstrike on the rebel-held neighborhood of Bab al-Maqam killed 10 people.

Meanwhile, air raids on a fuel market in the northern Idlib province killed at least eight people, including a media activist who used to report for the Al-Jazeera TV network.

In Aleppo, rebels fired hundreds of shells and rockets, with the clashes being the most intense near the old quarter and the city’s famed citadel. Syria’s largest city and once its commercial center, Aleppo has been bitterly contested between the warring sides in Syria’s civil war since the summer of 2012.