BEIJING: Dissident victims of China's crackdown on the 1989 Tiananmen Square protests have called for world pressure on Beijing to reverse the official verdict on the incident as its 20th anniversary is approaching. Failure to stand up to a rising China over the 'atrocity' of June 4, 1989, tacitly abets Communist Party repression, they said. 'So far, the international community... has adopted a policy of appeasement towards the Chinese government,' said Ding Zilin, whose teenage son Jiang Jielian was shot dead by the army. 'They are lenient towards this atrocity,' said Ding, 72, a former philosophy professor and now leader of the Tiananmen Mothers, which for 20 years has unsuccessfully pressured the government to be heard. Early on June 4, Chinese tanks and soldiers rolled into Tiananmen Square, killing hundreds, and possibly thousands, as the government moved to crush weeks-long pro-democracy demonstrations that had hugely embarrassed the ruling Communist Party. China's government has refused to provide a full account of the bloodshed, which remains a taboo subject in China and is only referred to officially as a 'political disturbance', if mentioned at all. But foreign pressure for a reassessment of the incident and rehabilitation of its victims, living or dead, is vital on the 20th anniversary if China is to have any hope of healing 'the wrongs of the past,' dissident Bao Tong said. 'A government that is not responsible to its own people cannot be responsible toward the rest of the world,' he said. Bao, 76, a former top aide to late Chinese leader Zhao Ziyang, was arrested after Zhao himself was purged for sympathising with the protesters. He has spent most of the last 20 years in jail, under house arrest or facing other restrictions. 'Not wanting to offend China means they cannot help China, cannot help China's people attain their own rights, and cannot help the world community gain a reliable, stable, peaceful member,' he said. 'This is not a good thing. If (the world) does not care, then they bear a large part of the responsibility.' In common with previous years, China is widely expected to tighten security as the anniversary nears, to thwart any calls for a reassessment. Dissidents have already reported being detained and harassed on the April 15 anniversary of the death of reformist communist leader Hu Yaobang. It was Hu's death that sparked the calls for political reform that led to the Tiananmen demonstrations. But Qi Zhiyong, who lost a leg after being shot on June 4, echoed other dissidents in saying the Communist Party would never come clean on its 'crimes' at Tiananmen. Qi, 52, calls the party a 'Chinese dynasty' committed solely to its own survival, through violence if necessary. 'As long as the party does not reassess their judgement on June 4 and acknowledge that it was a patriotic and democratic movement, then democracy cannot advance here. 'It means that all they say about advancing democracy and human rights are lies,' he said.