Sun Wenguang
This screen grab taken from AFP video footage shows former professor Sun Wenguang talking in his home in Jinan, east China's Shandong province on August 28, 2013.TANIA LEE/AFP/Getty Images

The Chinese government continues its crackdown on critics. In the latest incident, a retired academician was kidnapped from his home on Saturday night and is now reported to be missing.

Sun Wenguang was in the middle of a phone interview with the US television network Voice of America (VoA), where he was speaking live for a Chinese show when the police forced their way into his apartment and dragged him away. 

He was speaking on Xi's Africa policy, saying: "We don't go to Africa to spread money. Spreading money isn't good to our country and society. Not beneficial."

He was heard saying: "The police are here to interrupt again," as the police attempt to break down his door in Jinan in the eastern province of Shandong. Sun counted as many as eight intruders, and his final words were: "It's illegal for you to come to my home. I have my freedom of speech!"

Sun Wenguang talking in his home
former professor Sun Wenguang talking in his home in Jinan, east China's Shandong province on August 28, 2013TANIA LEE/AFP/Getty Images

The 80-year-old Sun, one of the oldest activists in China has been under regular surveillance for decades. He also co-signed the pro-democracy manifesto Charter 08, which was censored by the government and led to the arrest of co-author and Nobel Peace Prize winner Liu Xiaobo. Xiaobo became the first Nobel prize winner to die in custody since Nazi Germany when he passed away last year.

Last month, Sun wrote an open letter to Xi, criticising China's "chequebook diplomacy" in Africa. The letter became public just as Xi embarked on his trip to the continent. In 2009, he was beaten for sneaking out of his building to pay his respects to ousted Communist leader Zhao Ziyang on his fourth death anniversary.

Several media organisations, including the VoA, attempted to re-establish contact with Sun, both through his mobile and home phone, as well as through WeChat, the popular messaging service in China. Even calls to his former employer yielded no response.

In a statement, VoA said: "Everyone has the right to freedom of opinion and expression. This right includes freedom to hold opinions without interference and to seek, receive and impart information and ideas through any media and regardless of frontiers."

The dramatic recording has since gone viral on Twitter, prompting some US Senators to tweet about the aggressive crackdown on critics in China, as the ruling Communist Party is seen to nurture a cult-like personality around Xi Jinping.