China has detained a man for "publishing false stories" on an overseas news portal alleging gross rights abuses, police said Tuesday, the latest step in a wide-ranging crackdown on "Internet rumours". Xiang Nanfu, 62, had allegedly posted untrue stories on the Chinese-language site Boxun since 2009 which "seriously harmed the image of the state" and "caused a very bad influence", a statement on the Beijing police website said. Hundreds of bloggers and journalists have been arrested in recent months as part of a government-backed campaign to assert greater control over social media which has seen influential critics of Beijing paraded on state television. The campaign, which began last year, appears to be part of a concerted effort by China's ruling Communist party -- which maintains an iron grip on power -- to rein in criticism. Among the rumours that Xiang was alleged to have created was that the Chinese government "removed" organs from living people and "buried people alive", the statement said. Another claim was that more than 1,000 policemen violently expropriated land, including beating a pregnant woman to death, it added. Xiang, who is from Beijing, allegedly confessed to his crimes, the statement said. Boxun -- which often reports unsourced rumours -- issued a statement on its website describing Xiang as a "Boxun journalist". The statement denied the US-based website had reported on such organ removals or burying people alive, and linked the detention to China's recent Internet crackdown. "We noted that a lot of Chinese web users and dissidents were detained by authorities recently. This is a clear sign that human rights in China are quickly deteriorating," the statement said. At the start of the clampdown last year, officials told Internet celebrities with millions of followers to "promote virtues" and "uphold law" online. Soon after, Chinese-American billionaire blogger Charles Xue -- who regularly posted reform-minded comments on a variety of sensitive issues -- was arrested for suspected involvement in prostitution. Links between the Internet crackdown and the arrest of the popular blogger -- who had attracted 12 million online followers -- were routinely dismissed by state media. Xue was paraded on state television, which also broadcast an interviw with Pan Shiyi, another of China's most popular bloggers, in which he appeared contrite and warned of the dangers of "casual" online posts. Qin Zhihui, the first person to stand trial in the Internet crackdown, was jailed for three years last month after he confessed his guilt and made a lengthy statement of remorse, even thanking his detention centre. Under regulations announced last September, Chinese Internet users face three years in prison for writing defamatory messages that are re-posted 500 times. Web users can also be jailed if offending posts are viewed more than 5,000 times.