In Syria, government forces aided by Kurdish troops launched a major ground offensive and seized control of northeast Aleppo Monday from the rebels. The offensive appears to be a major turning point in the war, with the Syrian government now poised to retake control of all of Aleppo, which was once Syria’s largest city and its commercial center. U.N. humanitarian envoy Stephen O’Brien said as many as 16,000 people have fled eastern Aleppo in recent days amid the offensive and heavy bombing. Anti-government activist Zaher al-Zaher described the scene Monday as “doomsday.” If the Syrian government retakes all of Aleppo, the anti-government rebels will be left with little territory—only the northern province of Idlib and some areas in the provinces of Aleppo and Homs and around Damascus. The offensive came after eastern Aleppo has been besieged for weeks by Syrian government forces and under aerial attack by the Syrian air force and Russia.