Extremist Syrian Islamist forces have seized control over much of Aleppo, raising questions for the US government about its policy in Syria. The seizure of Aleppo is a military defeat for Assad and his allies, including Russia and Iran. Hayʼat Tahrir al-Sham (HTS), the group that secured the victory in Aleppo, is considered a highly dangerous organization by the US. The US government has designated both Iran and Syria as state-sponsors of terrorism. The Kurdish-led Syrian Democratic Forces (SDF) and the Kurdish force YPG are also present in Aleppo.