BEIJING - A former senior Chinese censor has claimed a major role in recording purged leader Zhao Ziyang's memoirs that decry the quelling of pro-democracy protests in 1989, adding to calls for the government to repent the crackdown.

Du Daozheng, reformist chief of the General Administration of Press and Publications in the late 1980s, said he was one of four retired officials who helped Zhao secretively record his memoirs before his death under house arrest in 2005.

Zhao's recollections, published abroad and sure to be banned in mainland China, challenge the ruling Communist Party's verdict that the student-led protests centered on Tiananmen Square in Beijing were a counter-revolutionary plot, and he calls the armed crackdown that ended them on June 4 two decades ago a tragedy.

In a statement explaining his role in making the memoirs, Du said it was time to rehabilitate Zhao, ousted in 1989 by Party conservatives who accused him of siding with the protesters.

At the major historic juncture of June 4, Zhao Ziyang acted responsibly to the Chinese nation, to history and to ordinary people, Du said in the statement, which will appear in the Chinese-language version of Zhao's memoirs to be published in separately administered Hong Kong this month.

Zhao's name remains taboo in mainland Chinese media and the government says his rift with Party conservatives over the protests was a grave error, Du notes.

In history, of course none of this can stand, Du said in the statement provided by Bao Pu, the son of a former senior aide to Zhao and also publisher of the Chinese version of the memoirs.

Du has joined a small but bold undercurrent within China openly urging the government to renounce the 1989 crackdown, when hundreds of demonstrators and bystanders died as troops and tanks surged down Beijing streets on the night of June 3-4.

A group of Chinese intellectuals has disclosed it recently met on the capital's outskirts to urge an end to official silence about the bloodshed 20 years ago.

Their speeches are now circulating on some Chinese-language internet sites and through email.

As time has passed, this massive secret has become a massive vacuum. Everyone avoids it, skirts around it, Cui Weiping, a Beijing-based academic, told the 20 or so participants, who included some of the nation's most prominent liberal scholars, among them Qian Liqun, a former professor at Peking University.

This secret is in fact a toxin poisoning the air around us and affecting our whole lives and spirit, said Cui.

Cui confirmed to Reuters on Wednesday she had made the speech at the meeting on May 10, and said as far as she knew none of the participants has been detained.

The Chinese government has been tight-lipped about the 20th anniversary of June 4, and on Tuesday a Foreign Ministry spokesman brushed aside questions on Zhao's memoirs, saying the official verdict on the demonstrations still stood.

Du, in his late 80s, eased censorship as head of press rules, and has long been associated with China Through the Ages (Yanhuang chunqiu), a magazine published in Beijing which has urged political liberalization.

He could not be contacted for comment on his statement. But a friend, speaking on condition of anonymity, said Du had also circulated the statement and described his role in persuading Zhao to record his memories on audio tapes copied and taken out of the mainland.

You have a duty to write this, Du said he told Zhao. It is your historic duty to leave a record for later generations.