With Wu Peifu's forces in retreat, the NRA directed itself toward Sun Chuanfang-controlled Jiangxi province, namely the city of Jiujiang and the provincial capital, Nanchang. Whilst Sun had been offered a non-aggression pact by the Guangzhou government, he was not willing to subordinate his administration to KMT rule. Consequently, whilst the siege in Wuchang was still ongoing, Chiang Kai-shek launched an attack across the Jiangxi border on 4 September. By 19 September, both Jiujiang and Nanchang had come under KMT control, hastened by the defection of Lai Shih-huang, one of Sun's generals. Despite these successes, the NRA offensive was forced into retreat as Sun arrived from Nanjing with reinforcements on 21 September. Sun retook most of the territory he had lost, brutally reasserting his authority by killing hundreds of students, teachers, and suspected members of the KMT, whose severed heads he displayed on spikes in public places.