China's Supreme Court takes aim at disgraced Zhou Yongkang and Bo Xilai

The Supreme People's Court has for the first time accused disgraced top cadres Zhou Yongkang, Bo Xilai and others of engaging in political activities "not approved" by the Communist Party.

The claim was made in the court's annual work report published on Wednesday in a section on the need to strengthen education on obeying discipline and avoiding corruption in the judicial system.

The report said that court staff should "clearly recognise the serious damage" caused by Zhou, Bo and others, who "trampled on the rule of law, undermined the party's solidarity, and engaged in political activities [not approved by the party]. It did not elaborate.

"The adverse influence of Zhou's violations of law and party discipline on the court's work should be thoroughly rooted out," it said.

Speculation is mounting that Zhou, the nation's former security tsar, and former Chongqing party chief Bo had formed factions to challenge the leadership of the party.

The day after the Politburo's decision to expel Zhou from the party on December 5, People's Daily said in a commentary that factions would not be tolerated.

Two days later, Wang Yongqing, the secretary general of the party's political and legal affairs commission, said that all cadres should learn from Zhou's case.

According to an article posted on the website of the Central Commission for Discipline Inspection, the party's graft watchdog, examples of activities not approved by the party and that hamper its solidarity include "forming factions" and "spreading rumours".

As a former member of the Politburo Standing Committee, Zhou, 71, is one of the highest profile figures so far caught up in the anti-corruption campaign kicked off by President Xi Jinping . He was expelled from the party last year, accused of crimes ranging from taking bribes to leaking state secrets.

The party has highlighted the problem of factionalism as many officials felled by the anti-graft campaign were connected to each other through the vested-interest groups they had formed.

After Ling Jihua, the one-time top aide to former president Hu Jintao was placed under investigation in late December, the Communist Party's 25-member Politburo pledged it would not tolerate political factions for the sake of personal business.