China is facing calls to reassess its suppression of the 1989 student protests after the death of purged Communist Party leader Zhao Ziyang.
Zhao's tearful appeal to students presaged his downfall
Zhao's secretary Bao Tong led the calls, backed by other pro-democracy activists and Taiwan. Japan urged China to move towards democratisation.
There is no official reaction from Beijing where there is suppression of news of Zhao's death, at 85.
Beijing recently stepped up security in Tiananmen Square and around his house.
Zhao had been under house arrest since the crushing of the pro-democracy protests in the square almost 16 years ago.
Correspondents say the authorities fear that Zhao's death might spark off new reformist demonstrations.
The former party leader, who reached the top after urging bold economic reforms, was removed after he opposed using military force against the demonstrators.
He was never again seen in public after 19 May 1989, when he went to Tiananmen Square and made a tearful appeal for demonstrators to leave.
The BBC's Louisa Lim says many will remember him as a symbol of thwarted political reform.
Hours after his death, Zhao's former secretary issued a statement attacking the Chinese authorities.
Mr Bao, who spent seven years in prison and now lives under government surveillance, said Zhao's isolation was a "showcase of shame" for Chinese justice and the Communist Party.
1989 TIANANMEN EVENTS
15 April: Reformist leader Hu Yaobang dies
22 April: Hu's memorial service. Thousands call for faster reforms
13 May: Students begin hunger strike as power struggle grips Communist Party
15 May: Soviet leader Mikhail Gorbachev visits China
19 May: Zhao makes tearful appeal to students in Tiananmen Square to leave
20 May: Martial law declared in Beijing
3-4 June: Security forces clear the square, killing hundreds
The party's "attempts to conceal the truth about the past only serve to reveal their weaknesses and their shamelessness", Mr Bao said.
The government of Taiwan, which China considers a renegade province, urged Beijing to reassess Zhao's role during the 1989 crackdown.
"We urge Beijing to re-examine the history and honestly face the truth at Tiananmen Square on 4 June 1989," cabinet spokesman Chen Chi-mai said.
Japanese Prime Minister Junichiro Koizumi called for China to make "efforts for democratisation".
China's government has issued just a brief statement, confirming Zhao's death. But the official Xinhua news agency instructed domestic radio and television not to carry the item.
There have been many grieving postings on internet bulletin boards. "Time will vindicate him," said one. "We will miss you forever," said another.
All were deleted speedily by chatroom monitors, our Beijing correspondent says.
On the streets however, many young people have never heard of Zhao Ziyang, she says.
One human rights activist, Frank Lu, says family members told him that Vice Premier Zeng Qinghong had visited Zhao on his deathbed.
That would indicate the close attention the top leadership has been paying to the fate of their former colleague, our Beijing correspondent says.
For the government, the main dilemma now will be what sort of funeral to give the former party leader.
Veteran dissident and democracy activist Ren Wanding called for a public funeral.
"The Chinese government, at the very least, should have an open and public funeral for Zhao Ziyang," said Jiang Peikun, whose 17-year-old son was killed during the 1989 riots.
China almost never commented on Zhao, who had once been expected to succeed Deng Xiaoping as the country's paramount leader. The deaths of other liberal leaders in China have tapped latent public frustration at the country's slow pace of democratic reform.
Protests flared when former Premier Zhou Enlai died in 1976, and pro-reform party leader Hu Yaobang's death in 1989 sparked the Tiananmen Square protests that ended Zhao's political era.