Exiled democracy activist Wei Jingsheng called at the weekend for greater unity among dissident groups. He told 100 other exiled dissidents they had to remember their responsibility to people on the mainland. 'We should put our minor arguments aside and be more unified. Our forces have to be strengthened,' said Mr Wei, who was addressing a candlelit vigil at the University of Toronto to commemorate victims of the June 4 crackdown nine years ago. Mr Wei said: 'Maybe one day we can go back to the mainland. Then, we have to tell our people we have done well overseas.' His comments came as two pro-democracy groups, the Chinese Alliance of Democracy and the Federation for a Democratic China, called for a world conference in New York in July, to try to form a coalition among exiles. Alliance chairman Frank Woo Fangcheng said he hoped all dissidents overseas would attend the meeting. 'We need such a coalition to push our work ahead,' he said. Both Mr Woo and Liu Qing, chairman of Human Rights in China, criticised Wang Bingzhang, one of the founders of the dissident magazine China Spring, who allegedly sneaked into the mainland and Hong Kong in February on a forged passport. Mr Liu said: 'He endangered dozens of activists in China by contacting them. The Chinese authorities arrested at least six activists and charged them with conspiracy. They're jailed in labour camps.' All three dissident groups plan to send members back to the mainland within the next 12 months. Mr Woo, who went to Beijing last month but was expelled, said: 'We will definitely do that.' Both Mr Woo and Mr Liu said they had no firm plans to go back although Mr Liu said: 'If we try to return China, we won't do this as a political stunt.' Shen Tong, a student leader in 1989, said he also planned to return before June next year. 'I'll go when the opportunity comes,' he said. The alliance and the federation were due to elect new chairmen today.