Seth Mydans, Jakarta – Faced with a huge student protest and a wild outbreak of rioting and arson, President B.J. Habibie said Saturday that he would take "firm action" to curb what he called subversive movements that threaten the country's stability.

On the day after soldiers killed at least eight demonstrators and wounded more than 100 others, tens of thousands of students and poor people filled a highway Saturday in front of the parliament building in what seemed an unfocused and unguided outpouring of discontent.

Their protests were supported by an unlikely ally: former President Suharto. "I resigned from my position to avoid bloodshed," Suharto was quoted by his half-brother, Probosutedjo, as saying. "Why does the government now cause bloodshed?" He said Habibie's government should apologize and listen to the demands of the protesters.

Later Saturday, in an echo of the riots that helped shake Suharto from office in May, residents of poor neighborhoods attacked shopping malls, banks, car dealerships, police stations and Chinese-owned shops in a surge of looting and vandalism. One police officer was reported to have been beaten to death.

But in contrast with the riots six months ago, troops and fire engines took action to quell the riots and douse the flames. Their ability to bring the first outbreaks of violence under control Saturday appeared to confirm suspicions that the earlier riots had been allowed and even instigated by elements of the military. In a statement to the nation, Habibie took a tough line against the demonstrators who had protested against a parliamentary session he had organized last week and had called for his resignation.

In a response that recalled the attitudes of his mentor, Suharto, he said the protests had revealed the presence of "subversive movements and actions that are endangering the unity and cohesion and the fundamentals of the life of the nation and state." He said he had ordered the military to "immediately take firm action." Soon afterward, the governor of Jakarta, Sutiyoso, announced a curfew over the weekend for the capital city from 10 p.m. until dawn.

A Western diplomat said it was unclear what groups Habibie might have in mind, or whether he or his military advisers were using accusations of subversion, as Suharto did, as an excuse for a crackdown.

Throughout Saturday, the military calmed the growing crowds of demonstrators with a tactfulness that contrasted with the sheer rage the soldiers had exhibited when they gunned down students Friday night. The key element, Indonesians said, was that most of the crowd control was handed over Saturday to the marines in their pink berets, a seasoned force that enjoys unique respect among the people. "Hooray for the marines," the students shouted Saturday morning, along with, "Down with Habibie."

The crowd of students and supporters swelled to as many as 50,000 during the day and was permitted to fill a highway outside the front gates of the now-empty parliament building. They sang and chanted into the night as the marines stood guard between them and the gates.

Even as they gathered there shortly after noon, plumes of black smoke were rising above the city's northern Chinatown and other poor areas. Ethnic Chinese residents and their shops and homes were particular targets of the May riots, in which nearly 1,200 people died and hundreds of buildings were looted, burned and vandalized. The rioting Saturday was less widespread, but at times the mobs of looters were so large that soldiers could only stand by and watch.

Military tents were burned in a park near the parliament building and an army truck was burned near the University of Indonesia.

At the Atrium shopping center, young men hurled rocks through the building's glass walls from a nearby highway overpass, which carried a red and white neon exhortation reading, "National Discipline." They smashed the windows and lobby of the Atrium Hotel at the back of the shopping center, forcing the evacuation of dozens of foreign guests. "This is a warning to Habibie about what could happen when the masses are angry," said Hariono, 19, a local resident, standing among a row of trees that had been uprooted from a median by rioters.

But it was at the Atrium that the contrast with last May was particularly noticeable. A cordon of marines moved through the crowd, clearing the area around the building, and a military jeep patrolled the newly empty streets urging people to return home. "It's time for prayer," repeated a soldier with a megaphone, as dusk fell. "Go home and don't cause any more damage. You know it will cost a lot and will take a long time to rebuild."