As the military began to remove barricades from the streets of Yangon, seemingly confident that the threat from the biggest pro-democracy demonstrations in two decades has passed, rights groups said up to 1,500 people are missing.

Amid the pervasive climate of fear in Myanmar - where troops patrol streets, news has been stifled, and Internet links cut - observers are struggling to assess just how many have been rounded up.

'We're hearing stories every night of raids, but by the morning it's hard to confirm,' said one Western diplomat.

But foreign diplomats believe at least several hundred Buddhist monks and political activists were taken away at the height of the bloody crackdown last week.

The Thailand-based Assistance Association for Political Prisoners, which has for years kept a close watch on political detainees in Myanmar's 43 prisons, estimates that up to 1,500 people were locked up last week.

'At least 85 protest leaders, over 1,000 monks, and between 300 and 400 students and activists were arrested,' said a spokesman.

The Buddhist monks at the forefront of what has been dubbed the 'saffron revolution' were forcibly disrobed and 'severely beaten, kicked and insulted', the group said.

And Human Rights Watch's Myanmar expert David Mathieson said the crackdown appeared to have been 'more well planned than last week's events suggested'.

'People were taken away during the demonstrations, people were arrested at night including in the monasteries, and people were arrested at the weekend at smaller demonstrations and as security forces cleared up the streets,' he said.

The Western diplomat said: 'There are fewer and fewer monks to speak to. What have they done to so rapidly silence the monks? That's the big question that needs to be answered.

'The monasteries are empty. They've had orders for senior monks to go back to their villages. They've really tried to disperse the monk community...The story gets hidden. It's hard to see which monks have disappeared.'

The diplomat also said the protest movement had been 'efficiently suppressed'.

Indeed, in Yangon yesterday, there was a clear sense that the protesters had once again failed in the face of the junta's overwhelming military might, which was last used in 1988 to crush a much larger uprising.

Despite continuing heavy security, many schools and shops reopened for the first time since the crackdown began last Wednesday, and buses returned to the streets.

'The people are angry but afraid - many are poor and struggling in life so they don't join the protests any more,' a 30-year-old university graduate known only as Thet, who drives a taxi, said yesterday.

Meanwhile, observers say many detainees have been taken to the city's notorious Insein prison, the Government Technological Institute, the Police Battalion No. 7 compound, Kyaikkasan race track and possibly other locations.

'There are enough old and now unoccupied government buildings since the move to Naypyidaw,' said one foreign observer, referring to the junta's sudden shift of the seat of government in late 2005.

As for the probable fate of the detainees, Mr Mathieson said that even at the best of times, Myanmar's prisons are sinister and overcrowded and that 'the conditions are horrendous, and torture and ill treatment are commonplace'.

AGENCE FRANCE-PRESSE, REUTERS, ASSOCIATED PRESS