Yan Xishan himself (along with most of the provincial treasury) was airlifted out of Taiyuan in March 1949. Shortly afterwards Nationalist planes stopped dropping food and supplies for the defenders due to fears of being shot down by the advancing Communists. The Communists, depending largely on their reinforcements of artillery, launched a major assault on April 20, 1949, and succeeded in taking all positions surrounding Taiyuan by April 22. A subsequent appeal to the defenders to surrender was refused. On the morning of April 22, 1949, the PLA bombarded Taiyuan with 1,300 pieces of artillery and breached the city's walls, initiating bloody street-to-street fighting for control of the city. At 10:00 am, April 22, the Taiyuan Campaign ended with the Communists in complete control of Shanxi. Total Nationalist casualties amounted to all 145,000 defenders, many of whom were taken as POWs. The Communists lost 45,000 men and an unknown number of civilian laborers they had drafted, all of whom were either killed or injured.