Between 12 and 14April, hundreds of communists in Shanghai were arrested and killed on the orders of Chiang in a disturbance that came to be called the "Shanghai massacre", effectively ending the alliance between the nationalists and the communists. The purge was condemned by the Wang Jingwei, now leader of the Wuhan government, formalising the split between the KMT leftists based in Wuhan and the KMT rightists, who subsequently established their own government in Nanjing. The precariousness of the NRA position in Nanjing was clear: at ceremonies held to commemorate the city's elevation to capital of China, warlord Zhang Zongchang's artillery bombarded the city's waterfront from across the Yangtze.