Exiled dissidents in the United States and Canada were preparing to commemorate the ninth anniversary of the June 4 massacre with candlelit vigils and calls for the release of all political prisoners in China. Exiled student leader Wang Dan will travel around North America to lead the activities in Boston, then in New York and finally Toronto. Mr Wang, one of the most famous 1989 student leaders, was only freed in April and immediately exiled to the US. In Boston, several hundred people including Mr Wang, Wang Xizhe, Wang Juntao and the Mayor of Boston took part in a candlelit vigil at Harvard University on Tuesday. Fellow activist Liu Gang, also a former 1989 student leader, gave a speech. Later, they headed towards the June 4 Square in Chinatown and presented wreaths at a monument to those who died in the crackdown. In New York, dissidents Wei Jingsheng and Harry Wu Hongda were to lead the ceremony in the 'Tiananmen Square' opposite the Chinese Consulate. A political declaration calling for faster political reform and the release of political prisoners in China will be read out. Speaking on Radio Free Asia, Mr Wei repeated his criticism of US President Bill Clinton's upcoming trip to China saying the president has chosen the wrong time to visit. 'He should not have chosen this time to visit . . . There has been no real progress of human rights in China,' said Mr Wei. 'And the Communist Party has not admitted its mistakes on June 4.' In Washington, apart from a candlelit vigil outside the Chinese Embassy, more than 50 representatives of dissident groups will hold a two-day conference to discuss how to unite all the forces of the overseas democratic movement. A similar commemoration in Toronto is set to draw more than 200 people. Smaller-scale activities are planned in Ottawa and in US west coast cities such as San Francisco and Los Angeles.