YANGON, Myanmar — About 20,000 protesters led by Buddhist monks and nuns Sunday mounted the largest anti-government protest in Myanmar since a failed 1988 democratic uprising, shouting support for detained pro-democracy leader Aung San Suu Kyi.

At one point a small crowd of about 400 — about half of them monks — split off from the main demonstration and tried unsuccessfully to approach the home where Suu Kyi is under house arrest. The monks carried a large yellow banner that read: “Love and kindness must win over everything.”

The march raised both expectations of possible political change and fear that the military might try to crush the demonstrations with violence, as it did in 1988 when thousands were killed nationwide.

On Saturday, more than 500 monks and sympathizers were allowed past barricades to walk to the house, where Suu Kyi greeted them from her gate in her first public appearance in more than four years. The meeting symbolically linked the current protests to the Nobel laureate’s struggle for democracy, which has seen her detained for about 12 of the last 18 years.

But any optimism on the protesters’ part was tempered Sunday when government security forces — who had kept a low profile for the past few days — deployed in force to block the new march to Suu Kyi’s house. The junta had clearly been trying to avoid provoking the well-disciplined, widely respected monks.

“In our country the monks are the highest moral authority. When the monks take the leading role, the people will follow,” said Soe Aung, a spokesman for the National Council of the Union of Burma, a coalition of opposition groups based in neighboring Thailand.

The crowd of about 400 people peacefully abandoned their attempt Sunday to get to Suu Kyi’s gate after being turned back at two different approaches blocked by barbed wire barricades.

Suu Kyi, 62, is the leader of the National League for Democracy party, which won a 1990 general election but was not allowed to take power by the military. She has been under detention continuously since May 2003.

The heavy security presence, including two lines of police — the rear line armed — and a police truck and fire engine, raised tensions after several days of a hands-off approach by authorities.

The protests began on Aug. 19 as a movement against economic hardship, after the government sharply raised fuel prices, increasing the overall cost of living. Arrests and intimidation saw the movement begin to falter until last week, when monks — who have long served as the country’s conscience — became the protests’ vanguard.

The march of 20,000 people downtown was led by 10,000 monks who gathered at the famous golden hilltop Shwedagon Pagoda before marching downtown to Sule Pagoda and past the U.S. Embassy among other places, witnesses said. For the first time, at least 100 white-robed nuns joined the demonstration.

Some monks shouted support for Suu Kyi, while a crowd of about 10,000 sympathizers marched along, some holding hands to form a human chain to protect the maroon-robed clerics.

While authorities did not intervene in Sunday’s march, plainclothes police trailed the marchers. Some, armed with shotguns, were posted at street corners along the route.