More than 100 people whose relatives were killed in China's 1989 Tiananmen Square crackdown hit out at the country's new president Xi Jinping in an open letter, days ahead of the anniversary of the deaths.
The Tiananmen Mothers group has for decades called on China's leaders to reverse their verdict on the 1989 pro-democracy protests in Beijing, when troops killed hundreds of protesters labelled as "counter-revolutionary".
In an open letter confirmed to AFP by a member on Friday, the group said Xi, who took office in March, was "not a real reformer".
"What we see, precisely, are giant steps backwards towards Maoist orthodoxy," it said. "This has caused those individuals who originally harboured hopes in him in carrying out political reform to fall into sudden disappointment and despair."
China's leaders, it added, "come one after another, as if through a revolving door; and as they move forward, they become ever more distant and outrageous, causing a universal feeling of despair to descend on the people from all sides".
The group, now 123 strong, has repeatedly called for China publish a full list of the names of those who died, and to compensate relatives.
"To this day, all our efforts have been in vain, we have received not a single response from the government," said the letter, posted on an overseas rights group's website ahead of the 24th anniversary of the crackdown on June 4.
China's government has so far provided no official toll for the repression, which was condemned throughout the world and led to the temporary isolation of Beijing on the international stage.
Unofficial estimates of the numbers killed range from around 200 to more than 3,000. The Tiananmen Mothers said in the letter they believed the higher figure was accurate.
Analysts say any official reassessment of the protests would be a key signal that Chinese leaders were willing to contemplate reform of the country's political system, which has been largely unchanged since the protests.
China's government maintains that the huge growth of the country's economy in recent decades has justified its authoritarian political model.
"We can see that the path we have chosen serves the fundamental interest of the Chinese people," foreign ministry spokesman Hong Lei said in response to a question about the letter on Friday. "The Chinese people enjoy extensive rights and freedom."
The Tiananmen Mothers group said last year that one of its members, the father of a 22-year-old man killed by soldiers during the crackdown, had committed suicide, leaving a note that detailed his continued distress over the killing.
"We will never give up, never stop, until June Fourth is finally reassessed, and the souls of the victims rest in peace," the letter said.