Authorities in the central Chinese province of Henan are holding a prominent rights activist in administrative detention after she retweeted news of ethnic unrest in the troubled region of Xinjiang, her husband said. Liu Linna, widely known by her pseudonym Liu Shasha, was detained on Monday by authorities in her home city of Nanyang after she went to apply for a permit to visit her husband in Hong Kong, a former British colony that still maintains an immigration border with the mainland. Liu's husband, political activist Yeung Hung, who captained a converted fishing vessel that carried nationalist activists to the disputed Diaoyu islands where they were detained and deported by Japan in October 2012, said she had been summoned by Nanyang state security police on suspicion of "spreading false information to disrupt social order." "On Monday morning I suddenly received a phone call from the National Security Bureau of Henan province," Yeung told RFA this week. "They told me that Shasha would be held for five days, due to her retweeting news about police in Xinjiang opening fire on Uyghurs." "[They] said that Liu Shasha had sent out a tweet on July 1 concerning a crackdown there on June 28, in which 15 people were killed." Yeung, who married Liu two months ago, said he was very concerned for his wife's safety. "They could use this as an excuse to keep her in detention," he said, adding that he was considering hiring a lawyer. Local authorities in China's Xinjiang region confirmed on June 30 that police fired at hundreds of ethnic minority Uyghur Muslims protesting the arrest of a young religious leader and closure of a mosque, acknowledging that up to 15 people may have been killed and 50 others injured in the incident retweeted by Liu. Uyghurs say they have long suffered ethnic discrimination, oppressive religious controls, and continued poverty and joblessness, blaming the problems partly on the influx of Han Chinese into the region. Online 'rumors' Last month, a 16-year-old boy from the western province of Gansu became the first person to be detained under a new set of rules issued by the judiciary targeting online "rumors." Blogger Yang Hui was held for seven days by Gansu police over a tweet accusing local authorities of improper conduct. Amid a crackdown on China's usually outspoken social media sites, the Supreme People's Court and state prosecution service issued guidelines on Sept. 9 warning that "rumor-mongering" is a crime punishable under law. Anyone posting information online deemed by the authorities to be "spreading rumors" or "defaming" another person may now be punished for a serious offense if the post is subsequently viewed at least 5,000 times or re-posted at least 500 times. Beijing-based dissident Hu Jia denounced Liu's detention. "The case of Liu Shasha demonstrates that Chinese authorities are furthering crackdown on dissidents," he said. "Liu Shasha was arrested only for retweeting a news item, and this fact itself is telling evidence that cyber control in China now has reached an unprecedented degree." Tireless activist Liu Shasha has worked to support a number of human rights causes across China in recent years. She was detained and beaten by Beijing police in February after she tried, alongside Yeung Hung, to visit Liu Xia, the wife of jailed Nobel peace laureate Liu Xiaobo under house arrest at her Beijing home. Holding a placard with the words "Liu Xia, everyone is behind you!" and shouting slogans through a megaphone, she and Yeung were quickly detained by police. But while Yeung was released back to Hong Kong officials, the feisty and outspoken Liu was handed over to officials and police from Henan, and was incommunicado for several days. She later told fellow activists she was suffering from perforated eardrums after police "pinned me to the floor and boxed my ears a great many times" during an altercation about her confiscated bank card. Liu Shasha was also instrumental in promoting Charter 08, a controversial document calling for sweeping political change in China that led to the jailing of Liu Xiaobo for 11 years in December 2009 on subversion charges.