A senior official suggested publicly for the first time yesterday that Beijing may soon formally announce it is investigating retired security tsar Zhou Yongkang for corruption. The hint, the strongest so far that the leadership will soon make the case public, was dropped after the South China Morning Post asked Lv Xinhua, spokesman for the Chinese People's Political Consultative Conference (CPPCC), whether Zhou was being investigated. At a press conference ahead of the annual session starting today, Lv sidestepped the question but stressed that "anyone who violates the party's discipline and the state law will be seriously investigated and punished, no matter who he is or how high ranking he is". Watch: Top Chinese official hints Zhou Yongkang to be probed for corruption He added: "Since last year, the Central Commission for Discipline Inspection and the Ministry of Supervision have conducted investigations or announced punishment for 31 top officials, including some at ministerial level. "Our serious investigation and punishment of party members and cadres, including some senior officials, indicates that what we stated was not empty words. I can only say so much so far. You know what I'm saying." It is the first time the Communist Party has openly commented on rumours surrounding Zhou. The Post revealed in August that party leaders had privately agreed to open a corruption investigation into the former member of the powerful Politburo Standing Committee. State media had remained tight-lipped but now some articles have started to link him and his son Zhou Bin - currently the subject of a graft probe. The announcement would mark the end of the party's unwritten rule that members of the Politburo Standing Committee, including retirees, can be exempted from investigation for economic crimes.