Fighters from Hezbollah and Iraq’s Shiite militias have deployed to Syria to support government forces, but it’s unclear if they are capable of turning the tide.

Even as Israel bombarded Syria, officials say the U.S. and Gulf countries were working to weaken its president’s alliance with Tehran. Rebels’ shock advance has dampened those hopes.

Iranian foreign minister has said that the country is ready to send troops to Syria and is awaiting official request from president Bashar Al-Assad. This comes as Iran's ally Russia is already helping the government forces fight Hayat Tahrir Al-Sham rebels in Syria.

Assad, as China also gave its backing to the regime. At least 300 fighters crossed from Iraq as Tehran said it would provide full support to the beleaguered dictator after rebel groups seized the city of Aleppo and charged south toward Hama and Damascus.