BEIJING // China's security chief supported policies that risked starting another cultural revolution, said a Community Party official who signed a letter calling for him to be sacked.
Zhou Yongkang, a leftist hardliner, should be removed from his position in charge of China's police, courts and secret services, and taken off the country's supreme nine-strong politburo standing committee, according to the letter that was released earlier this week.
Signed by 16 retired mid-ranking Communist Party officials from the southern province of Yunnan, the document, addressed to the Chinese president, Hu Jintao, and published on the internet, is believed to be highly unusual in calling for a high-ranking official to be sacked.
One of its signatories said he was concerned by Mr Zhou's support for "the Chongqing model".
It is the term for the policies the recently-sacked official Bo Xilai spearheaded when he was Communist Party chief of Chongqing municipality. It includes heavy state control of the economy and a crackdown on organised crime that critics said ignored the rule of law.
Also in Chongqing, there was a controversial initiative to encourage the singing of revolutionary "red songs" and the letter's signatory said he felt Mr Zhou supported "reviving the Maoist culture".
"We believe, given a free ride, this would start another cultural revolution," he said.
The former Chinese leader Mao Zedong oversaw repeated violent attacks on opponents and in 1966 launched the chaotic cultural revolution in which millions were victimised.
Since Mr Bo was stripped in March of his role as party chief in Chongqing, and later placed under investigation for "severe discipline violations", there has been widespread speculation in the foreign media that his close ally Mr Zhou could also be removed from office.
Mr Zhou, who is believed to have opposed Mr Bo's sacking as Chongqing party secretary, is seen as a leftist hardliner and a political opponent of more liberal officials such as the premier, Wen Jiabao.
Under Mr Zhou, crackdowns have been launched on civil society activists and China's budget for internal security has swelled to 701.7 billion yuan (Dh407.3 billion), more than the country's official defence spending.
The letter also said Liu Yunshan, a high-ranking propaganda official, should not be promoted during a leadership reshuffle that begins later this year.
Barry Sautman, a political analyst and associate professor at the Hong Kong University of Science and Technology, said it was likely a more senior official was behind the call for Mr Zhou to be ousted.
"If someone does attack a top leader, it means they're willing to get themselves in trouble or they have a backstage boss," he said.
"Someone is sponsoring them and someone has encouraged them and someone who has power."
The signatory said the letter probably had not reached its intended recipient, Mr Hu.
In any case, given that the officials who wrote it were not senior leaders, it was unlikely to have any effect, suggested Bo Zhiyue, author of China's Elite Politics and a research fellow at the East Asian Institute of the National University of Singapore.
"They're not really a factor in the elite politics of China," he said of those who wrote the letter.
Shortly before the letter's release, the Financial Times reported that Mr Zhou, who is to retire at the leadership handover, had already been forced to give up day-to-day control of his portfolio and was now just a figurehead.
Yet Mr Sautman cautioned that if a power struggle was under way, false rumours of an opponent's demise may be circulated to weaken them.
In a separate indication that hardliners are under pressure, the Wall Street Journal reported this week that certain army generals were being questioned over their links to Mr Bo. While Mr Bo is at the centre of a party disciplinary investigation, his wife, Gu Kailai, is accused of involvement in the killing of a British businessman.
Possibly of greater significance than the fate of individuals is whether the recent turmoil has strengthened liberals opposed to the Chongqing model.
Mr Sautman said after the leadership handover, in which seven of the politburo standing committee's nine members are to step down, there could be further economic reforms to curb the power of the state-owned enterprises.
In terms of political reform, he speculated elections could be introduced at township levels, in addition to the village elections already held.
Others think change is less likely, with Bo Zhiyue saying he doubted "there will be a resurgence of the liberal wing".