A Turkish air strike killed 11 civilians trying to leave Afrin in northern Syria on Saturday, the Syrian Observatory for Human Rights said, adding that more than 200,000 civilians have fled the city in less than three days. According to the British-based monitor, more than 280 civilians have been killed since the Turkey-led offensive against the Kurdish Peoples Protection Units (YPG) in the Afrin region began on January 20. Ankara has repeatedly said it takes the "utmost care" to avoid civilian casualties. "There was fierce fighting throughout the night on the northern outskirts of the city as the Turkish forces and their Syrian allies tried to break into the city," the Observatory said. The exodus continued on Saturday with at least 50,000 civilians fleeing the city since the early hours of the morning, it said. More than 200,000 civilians have fled Afrin in less than three days to escape the Turkish-led offensive, the war monitor added. Earlier this week, Turkey and its Syrian Arab rebel allies largely surrounded the enclaves sole city, which was home to some 350,000 people, including people displaced from other parts of the enclave already overrun. A single escape route remains open to the south to territory still held by the YPG or controlled by the Damascus regime. "Civilians are fleeing through the southern corridor," said Observatory director Rami Abdel Rahman. "The situation is terrifying," he added. On Friday, YPG official Redur Khalil and the Observatory reported a deadly airstrike on the general hospital in Afrin. But the Turkish military tweeted aerial footage and photographs of the hospital from Saturday morning, showing it was intact. The army said in a statement the YPG were trying to create a "negative perception" of the Turkish military.