More than 80 international scholars have upbraided Vietnam's Communist Party for condemning a prominent book publisher whose titles criticised socialism, a no-go zone in the Marxist country. Vietnam is one of the world's few surviving one-party communist states, and though it has embraced market reforms its politics on paper remain strictly socialist. The group of scholars issued a letter on Wednesday lending their support to 78-year-old publisher Chu Hao, who was denounced last month by the government for printing books on economics and political science deemed out of line. The government has called for Hao to be officially disciplined and confiscated or destroyed several of the volumes he printed. The rebuke prompted Hao to rescind his communist party membership of 45 years and sparked concern from the academic community abroad, which sent a letter of protest signed by 81 scholars, academics and researchers in 10 countries to Vietnam's top leaders. "We reject any assertion that these works present a threat to the stable or peaceful development of Vietnam," said the letter. "We find the accusations... to be unfounded and disturbing," it said. Hao was accused by the communist party's central inspection commission of publishing material that "runs counter to the viewpoints, policies and guidelines of the party (and) state". The state inspection commission singled out Friedrich Hayek's "The Road to Serfdom" for its apparent focus on the weaknesses of socialism and references to the former Soviet Union as a "fascist" state. It also condemned the publication of "Marx: A Very Short Introduction" by Peter Singer which the commission said disputes key Marxist ideologies. - 'Unjustifiable' - Hao has long been a thorn in the side of the communist party, which he accuses of stifling academic freedoms. The scholar, who runs the Hanoi-based Knowledge Publishing House, said the party has engaged in "unjustifiable, dishonest and degrading activities" in an open letter responding to the inspection commission last month. Hao declined to be interviewed by AFP when contacted this week. The ideological tussle prompted at least 10 other scholars, former officials and public figures to revoke their party membership in support of Hao, who served as vice science minister from 1996 to 2005. "The party has always tried to punish those with different opinions and this is no different," said former official Ha Quang Vinh who rescinded his 43-year party membership last month. He told AFP the move to dampen criticism from the party's intellectual elite was a bid by leaders "to protect their own seats". Vietnam's conservative communist party chief Nguyen Phu Trong has vowed to clean up his party, which he said has lost its way after years of mismanagement and high-level corruption. Dozens of bankers, businessmen and former officials have been thrown in jail under his tenure, with Hao the most prominent academic to fall afoul of the party under Trong.