The Kurdish-led Syrian Democratic Forces (SDF) have lifted a blockade they imposed last week on Syrian regime-held areas of the cities of Qamishli and Al-Hasakah, which they imposed last week. The blockades were imposed after fighting broke out between the SDF, who control most of northeastern Syria, and Arab tribal militias in Deir al-Zour, who were formerly allied to the SDF but are now backed by the Assad regime and its ally Iran. The agreement to lift them came following mediation by the regime’s other main ally, Russia. Most of Qamishli and Al-Hasakah are under the control of the SDF, but…