At least 49 people were killed during clashes between Syrian forces and militants from the Islamic State terror group in Aleppo province, a British war monitor reported on Thursday.The Syrian Observatory for Human Rights (SOHR) said that the victims comprised 17 security personnel and 32 IS extremists, Efe news reported.Hostilities have intensified in that area, as supporters of Syrian President Bashar al-Assad try to advance and take control of Maskanah town, in the eastern end of Aleppo, and other surrounding areas.Since Wednesday, Syrian authorities have taken over 12 towns and areas around the al-Jarrah military airbase.The airbase had fallen to the IS just four days ago, the SOHR added.