Chinese authorities in the northern region of Inner Mongolia have tried an ethnic Mongolian writer in secret on "separatism" charges, a rights group said on Friday. Lhamjab A. Borjigin, 75, stood trial on April 4 on charges of "separatism" and "sabotaging national unity," the New York-based Southern Mongolian Human Rights Information Center (SMHRIC) reported. "The trial started at 9:00 a.m. on April 4 and ended around 12:00 p.m. at the Shiliinhot Municipal People's Court," the group quoted a recorded audio message from Lhamjab as saying. "None of my family members were allowed to attend," he said. "I was denied the right to bring my lawyer to defend myself." A native of Heshigten Banner, a county-like division in Inner Mongolia, and a member of the state-backed Shiliingol League Literary Association, Lhamjab has been a prominent voice in ethnic Mongolian culture in China, as well as documenting the region's oral history. He specializes in survivor testimonies of the political violence and social chaos of the Cultural Revolution, publishing his book "China's Cultural Revolution" in 2006. Lhamjab said he had refused to speak Chinese during the court proceedings, and had "reluctantly" been allowed to bring an interpreter into the courtroom. "It was a typical closed-door trial," Lhamjab said. "Only eight people, namely three judges, three procurators, myself and my interpreter were present in the small courtroom with the door tightly closed." Lhamjab has rejected the charges pending against him, saying that he only wrote the historical truth. Case directly ordered by regional government The court has yet to announce its verdict in the case, which was brought under direct orders from the Inner Mongolia Autonomous Region government, according to Lhamjab. "When the [prosecutors] accused me of engaging in "national separatism,' "sabotaging national unity' and "illegal publication and illegal distribution,' I defended myself by asking whether those who committed the genocide in [Inner] Mongolia or the ones like myself who talked about this genocide should be considered [to be] "sabotaging national unity'," he said. "The [prosecutors] candidly told me that it is not up to them," Lhamjab said. "It was because the Autonomous Region Public Security Bureau and State Security Bureau are pressuring them to prosecute me on these charges." Lhamjab said he had maintained his innocence throughout the trial, and refused to plead guilty to any of the charges. "I am determined to appeal to the highest court because this is an unjust trial not only against me but also against our entire Southern Mongolians who have been subjected to a series of mass killing and political persecution but are not even allowed to speak of these atrocities." For his book, Lhamjab gathered oral testimonies of survivors of violence against ethnic Mongolians during the Cultural Revolution, a task that took him 20 years. The book accuses the ruling Chinese Communist Party of state-sponsored genocide in the region, detailing torture techniques and detentions in a brutal campaign that claimed the lives of at least 27,900 people and imprisoned and tortured 346,000. Lhamjab published the book unofficially, at his own expense, after state-run Chinese publishing houses refused to publish it. "The book became popular among Mongolians not only in [Inner] Mongolia, but also in the [neighboring] independent country of Mongolia," SMHRIC said. Destroying nomadic civilization Last year, an abridged audio version of the book went viral among ethnic Mongolians on Chinese social media platforms, especially WeChat, the group said. The authorities began confiscating copies of the book and placed Lhamjab under house arrest on July 11, 2018. The writers' group PEN America has called on Beijing to drop the charges and release Lhamjab. Ethnic Mongolians in exile have repeatedly also called on Chinese authorities to end human rights violations, systematic and institutionalized discrimination against ethnic Mongolians within China's borders, as well as longstanding policies aimed at ending their traditional, nomadic way of life. In a submission to the International Convention on the Elimination of Racial Discrimination (CERD), which is currently reviewing Beijing's record, SMHRIC called on the Chinese government to release all ethnic Mongolian prisoners of conscience, including members of herding communities who have been "arbitrarily arrested, detained, and imprisoned for defending their grazing land from illegal appropriation." The group is calling for the immediate withdrawal of all "extractive industries, tourist companies and power plants that not only occupy and appropriate large tracts of Mongolian grazing lands, but also devastate the ecosystem, deplete the underground water and pollute the air and water." It is also campaigning against the Chinese authoritie's "massive propaganda campaign to justify their destruction of nomadic civilization and ... the natural environment." Chinese government policies, the group said, are "based on deep-seated discrimination that characterizes Mongolian pastoralism as 'backward, archaic, unscientific and uncivilized' way of life and advertises the Chinese way of life as 'advanced, civilized and scientific'." The authorities should also prosecute "hate crimes and hate speech by Chinese individuals, private or public entities and government bodies against Mongolian language, customs, tradition, way of life and identity," it said.