The military government banned assemblies of more than five people and imposed curfews in Myanmar's two largest cities on Tuesday, after thousands of Buddhist monks and sympathizers defied orders to stay out of politics and protested once again.

Truckloads of soldiers converged on Yangon after the monks, cheered on by supporters, marched out for an eighth day of peaceful protest from Yangon's soaring Shwedagon Pagoda, while some 700 others staged a similar show of defiance in the country's second largest city of Mandalay.

"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, speaking on condition of anonymity fearing reprisals from officials. "People do not tolerate the military government any longer."

President Bush on Tuesday announced new U.S. sanctions against Myanmar, formerly known as Burma, accusing the military dictatorship of imposing "a 19-year reign of fear" that denies basic freedoms of speech, assembly and worship.

The U.S. already restricts imports and exports and financial transactions with Myanmar, as well as maintaining an arms embargo.

The 9 p.m. to 5 a.m. curfew and the meeting ban were announced late Tuesday through loudspeakers mounted on vehicles cruising through the streets of Yangon and Mandalay, said witnesses. The announcement said the measures would be in effect for 60 days.

The measures, after a week of relative inaction by the government, throws down a challenge to its opponents. Should the protesters defy the new regulation, the junta will have no choice but to use force or back down.

Using force, especially against monks, who are revered in predominantly Buddhist Myanmar, might intimidate some people, but could also stir anger against the regime at home and abroad. So far, the government had been handling the monks gingerly,

But backing down would also carry the risk of emboldening protesters even more.

Tuesday's protests came despite orders to the Buddhist clergy to halt all political activity and return to their monasteries.

The junta sent 10 truckloads of troops to Sule Pagoda, a focal point of the protests. Troops had been discreetly stationed in Yangon for the past few days, said diplomats.

"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. I've seen them myself. You can hear them. They shout," said a Southeast Asian diplomat who spoke on condition of anonymity, citing protocol.

The diplomat said the junta also limited bank withdrawals to once a week.

European officials and religious leaders worldwide, including the Dalai Lama and South Africa's Archbishop Desmond Tutu, intensified calls for the junta to refrain from a crackdown against the peaceful protesters.

According to an ethnic guerrilla commander, among the army divisions dispatched was the 22nd, which took part in the suppression of the 1988 uprising when the military fired on peaceful crowds and killed thousands, terrorizing the country.

"They could get there pretty quickly. By tomorrow, maybe today," said Col. Ner Dah Mya, a leader of the Karen National Union, which is fighting the central government. He was interviewed by telephone at the Thai-Myanmar border.

On Monday, the demonstrations in Yangon reached 100,000, becoming the biggest demonstrations since a pro-democracy uprising 19 years ago. The authorities did not stop the protests Monday, even as they built to a scale and fervor that rivaled the 1988 uprising. The government, has been handling the monks gingerly, wary of angering ordinary citizens in this devout, predominantly Buddhist nation.

Joining the monks Tuesday were members of the pro-democracy National League for Democracy headed by Aung San Suu Kyi as well as university students. They marched more than a mile to the Sule Pagoda under a scorching sun.

The demonstrations have escalated in just one week from a marginalized movement to mass protests drawing not only the monks but people from all walks of life.

In Mandalay, ordinary people were starting to join the monks or follow them on foot, motorcycles, bicycles and trishaws, though many still appeared too afraid to show their open support.

"I support the monks. However, if I join them, the government will arrest me," said a man selling belts at a Mandalay market. He declined to give his name, fearing reprisals from officials.

The head of the country's official Buddhist organization, or Sangha, issued a directive Monday ordering monks to stick to just learning and propagating the faith, saying young monks were being "compelled by a group of destructive elements within and without to break the law," the newspaper said.

These agitators included members of the National League for Democracy, remnants of the defunct Burmese Communist Party and some foreign radio stations, the minister was quoted as saying.

The current protests began Aug. 19 after the government sharply raised fuel prices in what is one of Asia's poorest countries. But they are based in deep-rooted dissatisfaction with the repressive military government that has ruled the country in one form or another since 1962.

The protests over economic conditions were faltering when the monks last week took the leadership and assumed a role they played in previous battles against British colonialism and military dictators.

At first the robed monks simply chanted and prayed. But as the public joined the march, the demonstrators demanded dialogue between the government and opposition parties, freedom for political prisoners, as well as adequate food, shelter and clothing.

The fleeting appearance of Nobel Peace Prize laureate Suu Kyi at the gate of the Yangon residence where she is under house arrest squarely identified the protests with the longtime peaceful struggle of her party, the opposition National League for Democracy. She has been under detention for 12 of the past 18 years.