A previous plot to overthrow Chinese President Xi Jinping has reportedly been disclosed by the head of China’s securities watchdog agency.

UPI said that Liu Shiyu, the chairman of the China Securities Regulatory Commission, accused six party leaders on Thursday of plotting a coup against Xi.

Liu made the comments at a panel discussion that was held as part of the pivotal 19th Party Congress in Beijing. They were made in the context of extending congratulations to Xi for working to “save socialism” in China by foiling the plot.

The congress, which began Wednesday, will determine the composition of the party’s all-powerful Politburo Standing Committee (PSC) and cement Xi’s rule for another five years.

The six onetime party leaders in the plot have since been punished.

Liu is said to have identified the ex-party boss of megacity Chongqing, Sun Zhengcai, as the plot’s leader. Sun was once a front runner for a place in the PSC.

Xi “addressed the cases of Bo Xilai, Zhou Yongkang, Ling Jihua, Xu Caihou, Guo Boxiong and Sun Zhengcai. They had high positions and great power in the party, but they were hugely corrupt and plotted to usurp the party’s leadership and seize state power,” Liu said.

Though rumors of such a plot against XI have been circulating in China, Liu, on Thursday, became the first Chinese senior official to accuse Sun of trying to take over the party. Sun was expelled from the party “for serious discipline violations” and detained by judicial authorities, Xinhua reported in September. No other details have been disclosed since then.