We can't just allow people to demonstrate whenever they want to

Deng Xiapping

Transcripts of high-level meetings between April and June that year - reportedly leaked by senior moderates in the ruling party - give an unprecedented insight into Chinese power politics.

The documents show how Prime Minister Li Peng and other hardliners persuaded the ageing leader, Deng Xiaoping, of the necessity to take action, and how he forced the liberal party secretary, Zhao Ziyang, out of the leadership.

Deng (with Mikhail Gorbachev): Feared "house arrest"

Mr Deng is revealed to have insisted nervously that there must be no killing in Tiananmen Square.

"Anarchy gets worse every day. If this continues, we could even end up under house arrest," he tells a meeting of his inner circle.

But one of the eight elders in the leadership, Wang Zhen, says: "Those goddam bastards; we should send the troops right now to grab those counter-revolutionaries!"

Experts authenticate papers

After the troops were sent in, the papers quote Mr Li - who is now the second-ranking member of the Communist Party hierarchy - as saying that 200 civilians had been killed in the surrounding area.

Those figures are line with the official account of casualties but human rights organisations say several hundred people died in the square itself - the official line from China has always been that nobody was killed there.

The demonstrations were the most serious challenge to Communist rule

The documents - to be published in the prestigious American journal Foreign Affairs and in book form - have been scrutinised by experts who are convinced of their authenticity.

Columbia University professor of political science Andrew Nathan, who edited the book, says in his introduction that the transcripts display "an internal coherence, richness and human believability that would be almost impossible to fake".

There has been no official reaction in China to the publication. The leadership insists it made a correct historical judgement in suppressing the demonstrations, which it argues would have endangered the economic development enjoyed by China during the past decade.

Ousting Zhao

Correspondents say any reassessment by Beijing of the events of 1989 is out of the question with the continuing presence of Li Peng as number two.

The way the liberal Zhao Ziyang was forced out of his position as party secretary by Mr Li reveals a deep rift in the leadership after the massacre.

The military suppression shocked the outside world

"I think Comrade Ziyang must bear the main responsibility for the escalation of the student movement, as well as for the fact that the situation has become so hard to control," Li says.

Deng agrees that Mr Zhao's position has been "exposed completely".

"He obviously stands on the side of the turmoil, and in practical terms he has been fomenting division, splitting the Party, and defending turmoil," he says. "It is lucky we're still here to keep a lid on things."

The documents show how the leadership went on to vote in the current overall leader, Jiang Zemin, as party secretary, replacing Mr Zhao.

BBC foreign affairs editor John Simpson says the manoeuvre is shown as having been strictly unconstitutional - and exposing that, he says, may be the real reason for the revelations.