Iran is at a critical juncture amid the Sunni insurgent offensive in Syria, as it navigates the realities about its weakened ally Hezbollah and the complexities of its own presence in a geopolitical power play that involves multiple actors competing for different agendas.

Iran has thrown its support behind Syria's government after thousands of insurgents took control of the country's largest city of Aleppo.

Syria launched airstrikes to push back the rebels who have taken the northern city of Aleppo in a surprise strike, prompting ally Iran to offer support.