Summary
The Syrian army advanced toward the Turkish border on Monday in a major offensive backed by Russia and Iran that rebels say now threatens the future of their nearly five-year-old insurrection against President Bashar Assad.
The Syrian military and its allies were almost five km (3 miles) from the rebel-held town of Tal Rafaat, which has brought them to around 25 km (16 miles) from the Turkish border, the rebels, residents and a conflict monitor said.
The assault around the city of Aleppo in northern Syria has prompted tens of thousands to flee towards Turkey, which is already sheltering more than 2.5 million Syrians, the world's largest refugee population.
Aleppo, Syria's largest city before the war with 2 million people, has been divided for years into rebel and government-held sections.
Turkish President Tayyip Erdogan was quoted at the weekend as saying Turkey was under threat and Ankara has so far kept the border crossing there closed to most refugees.
After around a week of heavy Russian airstrikes, Syrian government troops and their allies broke through rebel defences to reach two Shiite towns in northern Aleppo province on Wednesday, choking opposition supply lines from Turkey.
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