Chinese human rights activist Hu Jia, who was freed from jail on Sunday, is being held under conditions \"equivalent to house arrest\", his wife says. Zeng Jinyan told the BBC there were now \"an extraordinary number\" of police outside the family\'s flat in Beijing. Mr Hu served a three-and-a-half-year sentence for inciting subversion. The charges related to five articles he had written as well as interviews with journalists in which he was critical of the Chinese authorities. Mr Hu has long been one of the most prominent critics of China\'s Communist Party, saying it \"presides over a system where torture and discrimination are supported by a sophisticated secret police\". The 37-year-old has also campaigned for people with Aids, and for the protection of the environment. \'Careful\' In a brief online message Ms Zeng said the couple had \"limited freedom\", adding that \"right now, this is equivalent to house arrest\". The first picture of Mr Hu since his release, obtained by the BBC, shows the human rights activist inside his flat, pleased at being out of prison. Mr Hu is said to suffer from cirrhosis of the liver and was denied early release from prison for treatment. His wife told the BBC she was trying to arrange a hospital appointment for him but will have to apply for permission to leave their house to travel to see a doctor. She said: \"He will gradually integrate with the society again. He\'s a little slow right now, in all aspects (not just physical). He\'s not used to it yet. He needs a few days.\" In a telephone conversation with a Hong Kong TV station, Mr Hu said his family is pressuring him not to resume his activism. \"They told me today to live an ordinary person\'s life, and not to clash with the system, because the system is very, very cruel - for example using a government\'s power to violate citizen\'s rights with no hesitation,\" he said. He said he could only say he would be careful. Mr Hu is believed to have been short-listed in the past as a candidate for the Nobel Prize. The president of the European Parliament, which has awarded Mr Hu its top human rights award, the Sakharov Prize, said it was important that Mr Hu and other Chinese activists should be allowed to carry on \"everyday life without further hindrance\". Last week, the outspoken artist Ai Weiwei was also freed. Mr Ai\'s detention in April prompted a global campaign for his release. The Chinese authorities say Mr Ai has confessed to tax evasion. The BBC\'s Damian Grammaticas in Beijing says it appears that Mr Hu, like Mr Ai, has been silenced, put under close surveillance and banned from talking to the media. About two dozen people in China have been seized this year and held at secret detention centres, including Ai Weiwei, several lawyers and activists, our correspondent says. Most of those released have refused to talk, apparently pressured or intimidated into staying silent. Some are still missing