China’s senior-most general, Zhang Youxia, is under investigation for alleged corruption, abuse of power, and leaking sensitive nuclear-weapons data to the United States, according to people familiar with a closed-door military briefing.

Authorities say Zhang accepted large bribes in exchange for promotions, helped elevate former Defense Minister Li Shangfu, formed political cliques that undermined party unity, and oversaw misconduct within the military procurement system.

The probe was triggered in part by evidence linked to Gu Jun, a nuclear executive also under investigation, which allegedly connected Zhang to a serious security breach in China’s nuclear sector.

Zhang’s downfall marks an unprecedented purge of China’s military high command under Xi Jinping, signaling a zero-tolerance approach even toward longtime allies and “princelings,” the Wall Street Journal has reported.

Analysts say the sweeping crackdown consolidates Xi’s control over the armed forces but may weaken near-term military readiness due to the hollowing out of senior leadership.