Supported by artillery and armor, the PAVN continued to march towards Saigon, capturing the major cities of northern South Vietnam at the end of March—Huế on the 25th and Đà Nẵng on the 28th. Along the way, disorderly South Vietnamese retreats and the flight of refugees—there were more than 300,000 in Đà Nẵng—damaged South Vietnamese prospects for a turnaround. After the loss of Đà Nẵng, those prospects had already been dismissed as nonexistent by American CIA officers in Vietnam, who believed that nothing short of B-52 strikes against Hanoi could possibly stop the North Vietnamese.