Twenty thousand people, including nuns, monks and ordinary Burmese, marched through the streets of Rangoon on Sunday, demanding freedom for the Nobel Laureate, Aung San Suu Kyi.
The protest was seen as a dramatic escalation of the country's Buddhist-led "saffron revolution".
Riot police and barbed wire barricades blocked the protestors from approaching the home of the detained democracy leader Suu Kyi.
Ten thousand monks, joined by about the same number of secular supporters, marched from the Shwedagon Pagoda through the centre of Burma's largest city, in the largest anti-government demonstration since the bloody suppression of the first democracy movement in 1988.
After heavy handed efforts to put down demonstrations earlier in the month, the military junta has recently been more restrained, even allowing a large group of monks to march past the house of the detained Suu Kyi and pray with her on Saturday.
But the rapidly growing scale of the demonstrations - from a few thousand a week ago to tens of thousands over the weekend - inevitably raises fears of another attempt at suppression by a dictatorship which usually tolerates no challenge whatsoever to its authority.
"We want the people to join us," the monks chanted.