LEIPZIG (AFP).- Tens of thousands joined a candlelight procession on Thursday marking a watershed mass protest 25 years ago that helped bring down the Berlin Wall a month later.

European leaders and former dissidents joined local residents in a day of celebrations culminating in a reenactment of the iconic march in the eastern German city of Leipzig, while warning of the recent rise in Cold War-style tensions with Russia.

The ceremonies came one month to the day before the reunified capital marks a quarter century since the communist authorities threw open the despised barrier in Berlin.

In that momentous autumn of 1989, successive Mondays saw mounting demonstrations against the Stalinist state.

The peaceful protest in Leipzig of 70,000 people on October 9, the largest turnout to date, met with stunned disbelief from the East German authorities and Soviet troops.

It proved a turning point after months of unrest which had sparked fears of a bloody crackdown as seen in Tiananmen Square in Beijing that June.

German President Joachim Gauck, who was himself a pro-democracy pastor in the communist East, called the night of October 9, 1989 "magical" and paid tribute to the demonstrators' courage.

"They were familiar with the arrogance of power -- an order to shoot would in no way have been unthinkable," he told a ceremony at the city's Gewandhaus concert hall.

"But they came anyway -- tens of thousands overcame their fear of the oppressors because their longing for freedom was bigger."

Gauck said the "young demonstrators in Hong Kong" today demanding more democratic rights were acting in the same spirit.

He was joined by his counterparts from Poland, the Czech Republic, Slovakia and Hungary, as well as former US secretaries of state James Baker and Henry Kissinger, who was born in Germany.

The opening of the Berlin Wall on November 9, 1989 brought the long-demanded liberty to travel for Easterners and would usher in the end of the regime, and Germany's reunification the following October.

Gentle power of street

Baker, who was the top US diplomat from 1989 to 1992, called the Leipzig rallies the "beginning of a march to freedom that didn't stop until there was freedom for the people of the GDR and of other captive nations of Central and Eastern Europe", using the acronym for communist East Germany.

But he warned that many former Soviet states were now experiencing "angst and anxiety" over Russian military action in Ukraine.

"I don't think we're going back into a full Cold War situation. I sure hope we're not," he told reporters.

"But I would remind you that for 15 years after 1991, Russia and the West were very closely cooperating. During those 15 years, we had a Europe that... was whole and free, and I don't know why we can't get back to it."

The leaders gathered later at Saint Nicholas Church for prayers for peace, whose weekly occurrence at the same site 25 years ago helped touch off the popular movement.

Polish President Bronislaw Komorowski said he hoped those pushing for democratic "freedom in the Middle East and also Ukraine" could take a page from 1989's East Germans.

The Leipzig chants of "We are the people" -- a direct rebuke to the leaders of the "people's republic" -- became a rallying cry for a beleaguered nation of 17 million ready for change.

"I thought immediately, this is irreversible," artist Matthias Buechner, 61, told AFP, recalling soldiers and police officers simply watching the demonstration in shock.

"The gentle power of the street would take over power in the country. But that it would all go so quickly took us all by surprise."

With reunited Germany now led by two easterners, Chancellor Angela Merkel and Gauck, the country still sees unification as a work in progress, despite growing economic and social equality between its two halves.