Burma's junta poured troops and police armed with rifles into central Rangoon today in an attempt to end the biggest demonstrations against military rule in nearly 20 years.
Security forces surrounded the Sule Pagoda, focus of two days of mass protests led by thousands of maroon-robed monks, and appeared to be ready to seal off the area, witnesses said.
In another possible sign of a looming clash, a well-placed source said detained democracy leader Aung San Suu Kyi had been moved to the notorious Insein prison on Sunday, a day after she appeared in front of her house to greet marching monks.
Over 10,00 monks, joined by thousands of bystanders, march to the centre of Rangoon today in anti-government protests
Some analysts said the junta was caught off guard by the speed with which sporadic marches against a sharp hike in fuel prices in mid-August had mushroomed into mass demonstrations against 45 years of military rule in the Southeast Asian country formerly known as Burma.
As the international community urged the generals to avoid a repeat of a bloody crackdown on protests in 1988 and the United States announced fresh sanctions against the junta, the UN human rights investigator for Burma said he feared "very severe repression."
"It is an emergency," said Paulo Sergio Pinheiro, singling out China as a regional power that would play a "positive role" to defuse the crisis and calling for "quiet diplomacy" by countries including the United States.
This evening, soldiers moved in on the Sule Pagoda after hours of peaceful protest by tens of thousands of people who turned up despite the junta's threat to use force.
The area around the pagoda, which includes City Hall, was the scene of the worst bloodshed during a crackdown on nationwide pro-democracy protests in 1988 in which 3,000 people are thought to have been killed.
Today echoed with reminders of one of the darkest days of Burma's modern history.
Vehicles with loudspeakers toured Rangoon, blaring threats of action under a law allowing troops to break up illegal protests. People came in huge numbers anyway and, in Taunggok, a coastal city 250 miles (400 km) to the northwest, witnesses said about 40,000 monks and civilians took to the streets.
Protesters were led in Rangoon by 10,000 monks chanting "democracy, democracy" and, in a gesture of defiance, some waved the bright red "fighting peacock" flag, emblem of the student unions that spearheaded the 1988 uprising.
The streets were lined with people clapping and cheering as the column of monks stretched several blocks on their march from the Shwedagon Pagoda, the nation's holiest shrine and symbolic heart of the campaign, to the Sule Pagoda.
British Ambassador Mark Canning told Reuters two of the junta's ministers had assured him the protests "would be dealt with in a 'correct' fashion, whatever that means."
But the chilling message behind the loudspeaker warnings was lost on nobody in Rangoon, a city of 5 million people, a week after monks started marching in protest against warning shots fired over the heads of fellow monks.
"I'm really worried about the possible outbreak of violence," one street vendor said.
"We know from experience that these people never hesitate to do what they want." Ethnic Karen rebels on the Thai border said that troops of the 22nd Division had been redeployed to Rangoon.
That division played a major role in the 1988 carnage and the report lent weight to threats issued by the religious affairs minister, Brigadier-General Thura Myint Maung.
State radio quoted him as saying action would be taken against senior monks if they did not control their subordinates in protests he said were fomented by political extremists.