The Syrian army says dozens of its soldiers were killed in a major attack by rebel forces who swept into the country's second-largest city, Aleppo. The offensive is being seen as a major challenge to President Bashar al-Assad. Assad has vowed to defeat terrorists during separate phone talks with leaders from the United Arab Emirates and Iraq on recent developments in Syria. Russia's Defense Ministry says its air force carried out strikes on Syrian rebels in support of the country's army.