Fresh from the success of the Northern Expedition to overthrow the warlords, Chiang turned on the Communists, who by now numbered in the tens of thousands across China. Ignoring the orders of the Wuhan-based KMT government, he marched on Shanghai, a city controlled by Communist militias. Although the Communists welcomed Chiang's arrival, he turned on them, massacring 5000 with the aid of the Green Gang.[85][88] Chiang's army then marched on Wuhan, but was prevented from taking the city by Communist General Ye Ting and his troops.[89] Chiang's allies also attacked Communists; in Beijing, 19 leading Communists were killed by Zhang Zuolin, while in Changsha, He Jian's forces machine gunned hundreds of peasant militiamen.[90][91] That May, tens of thousands of Communists and their sympathisers were killed by nationalists, with the CPC losing approximately 15,000 of its 25,000 members.[91]