Meanwhile, also in 764, Pugu Huai'en, then at Hezong (河中, in modern Yuncheng, Shanxi), formally rose against Tang imperial troops, against his mother's advice. An attack against Yuci (榆次, in modern Jinzhong, Shanxi), commanded by Pugu Huai'en's son Pugu Yang (), however, was repelled by Tang forces, and Pugu Yang's own soldiers killed him. Pugu, believing he was facing defeat, took his troops, largely from Shuofang Circuit (朔方, headquartered in modern Yinchuan, Ningxia), back to its headquarters at Lingwu and dug in there; he thereafter remained a threat to the Tang imperial government, although Emperor Daizong, still hoping that he would resubmit, never formally declared him a renegade, and when Pugu's mother, who did not follow him to Lingwu, died, he buried her with honors.