President Xi Jinping has called on the mainland's judges and law enforcement leaders to root out corruption from their own ranks - a warning that comes amid a wide-ranging graft probe into the country's former security tsar. In a speech to an annual work conference on political and legal affairs, Xi urged officials to enforce the law impartially, promote transparency and be open to public oversight to eliminate judicial corruption. "Officials at all levels are forbidden to overstep the limits of the law, to abuse their power or to bend the law for personal gain," Xi said, according to state media. He pledged to "get rid of graft in the political and legal sector and clean up the black sheep of the family". Xi's remarks coincide with a widely reported corruption investigation centred on Zhou Yongkang, who until 2012 was a member of Communist Party's supreme Politburo Standing Committee. He also led the Central Political and Law Commission, which oversees law enforcement and the judiciary. Last month, former deputy national police chief, Li Dongsheng - a close associate of Zhou's - was sacked from his public offices and placed under a corruption probe. He was the highest-ranking law enforcement official to fall from grace during a corruption crackdown that has also hit Zhou's former powerbases in Sichuan and the state oil industry. The two-day annual conference Xi spoke at was attended by judicial and law enforcement officials from all over the country. Among those in attendance was Procurator General Cao Jianming, who was visible on China Central Television footage sitting in the front row of the audience. Cao's future has been the subject of intense speculation due to his perceived links to Zhou. Xi told the group that ensuring social stability was the fundamental focus of the country's political and legal affairs. But he said promoting social justice and equality were also core values. "People's demands for their lawful interests must be properly handled," Xi said. "The role of the law in solving conflicts should be strengthened." Liu Xiaoyuan, a prominent Beijing-based rights lawyer, wrote in his Sina Weibo account that despite Xi's encouraging rhetoric, he questioned how officials could act on Xi's remarks. "[In his speech] on the loyalty of the law enforcement, law came after the party, the state and the people," Liu wrote.