"They are in full battle gear and they have shields and truncheons. Since two or three days, you could see they are rehearsing anti-riot formations," a South-East Asian diplomat said of the troops deployed around the Sule Pagoda.
"I think all the people of Myanmar must act to get democracy for a better life"
aprat_1992, Denpasar, Indonesia
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Government vehicles mounted with loudspeakers were reported to be patrolling Yangon's streets saying monks had been ordered not to take part in "secular affairs" and accusing certain elements of trying to instigate unrest.
The curfew order cited a legal clause which would allow the protests "to be dispersed by military force".
An estimated 50,000-100,000 protesters marched through the streets of Yangon on Monday in the biggest demonstration yet against the military government.
"The protest is not merely for the well-being of people but also for monks struggling for democracy and for people to have an opportunity to determine their own future," one monk told The Associated Press.
"People do not tolerate the military government any longer."
The first known activist rounded up after the curfew was a comedian famed for his anti-government jokes.
Zargana was taken away from his home by authorities shortly after midnight.
Zargana led a committee that provided food and other necessities to protesting monks along with actor Kyaw Thu and poet Aung Way, whose fates were not known.
Reports from inside the country indicated that the government had cut off internet access and there were also unconfirmed reports that Aung San Suu Kyi, the country's democracy leader and Nobel Peace laureate who has been under house arrest, had been moved to prison.
Meanwhile, the Burmese Media Association (BMA), a US-based network of Burmese journalists in exile, said private newspapers and magazines in Yangon had been ordered to publish a statement denouncing the protests.
"All journals and periodicals were also ordered by the information ministry to carry an announcement in which we have to state that we are not a part of the association and are not interested in taking part in the protests," the BMA quoted a journalist inside Myanmar as saying.
It added that the military government had warned the media not to participate in the protests or support the protesters.
Maung Maung Myint, the BMA's president, called the order "a severe violation of personal and media freedom".
On Tuesday, George Bush, the US president, announced that Washington would tighten sanctions on Myanmar's military government.
"This morning I'm announcing a series of steps to help bring peaceful change to [Myanmar]," Bush said in a speech to the UN General Assembly in New York on Tuesday.
"The United States will tighten economic sanctions on the leaders of the regime and their financial backers, and we will impose an expanded visa ban on those responsible for the most egregious violations of human rights as well as their family members."
A source told Reuters on Tuesday that Aung San Suu Kyi, the leader of the opposition National League for Democracy, was moved on Sunday to a prison from her home, where she has been held under house arrest.
On Saturday, police temporarily removed barricades at the end of Aung San Suu Kyi's street, allowing protesting monks to pass her home.
Aung San Suu Kyi greeted the monks as they passed, but police resumed guarding the entrance to the street soon afterwards.
The moves against the demonstrators come after Brigadier-General Thura Myint Maung, Myanmar's religious affairs minister, told Buddhist leaders that "action will be taken" to prevent further protests.
"We warn the monks and the people not to participate in protest marches. We will take action under the existing law," he was quoted as saying.
Human rights groups reported on Monday that government agents had been preparing to infiltrate the protests in order to spark trouble and justify a crackdown.
Irene Khan, the secretary-general for Amnesty International, a human rights organisation, appealed to the UN Security Council to immediately send a mission to Myanmar.
"The high risk of a crackdown against the demonstrators makes it imperative for the international community to act urgently," Khan said, adding that China, Japan and India had a role to play in ensuring stability in Myanmar.
'Pretext for crackdown'
The London-based Burma Campaign UK said it had a received reports of soldiers ordered to shave their heads, apparently to pose as monks and infiltrate the protests.
About 90 per cent of Myanmar's population is Buddhist.
At some point in their lives, every Buddhist male is expected to join the monk hood or 'Sangha'.
Every village or neighbourhood has its own pagoda and monastery, which traditionally serves as the focus for community life and the main centre for education.
In recent years rising levels of poverty have raised demand for the free education provided by the monasteries.
"They would start rioting or attacking police, providing the regime with a pretext for a brutal crackdown on protesters," the group said.
The protests were initially triggered by a massive hike in the price of fuel on August 19, but have developed into a more deeply-rooted outpouring of dissent led by groups of monks.
In the space of a month the protests have become the biggest challenge to Myanmar's military government in almost two decades.
Charles Petrie of the United Nations' Development Programme in Myanmar told Al Jazeera the demonstrations were an expression of the frustrations felt by many in the country after years of poverty and hardship.
"The monks have brought out into the open the issues that are of real concern to a significant portion of the population," he said.
"There is an underlying suffering that is now being expressed."