The government of Gen. Augusto Pinochet imposed a strict curfew and ordered the Army into the streets tonight to control a mass protest against military rule that went ahead despite Pinochet's vow to prevent it.

Defying official warnings and an aggressive government effort to dismantle opposition leadership, students battled police and blocked streets near campuses during the day. Dozens of persons built flaming barricades of stone and wood in residential neighborhoods.

There were no immediate reports on arrests or injuries.

After the 8 p.m.-to-midnight curfew went into effect, machine-gun fire could be heard in the streets of downtown Santiago. The streets, normally packed with crowds at nightfall, were almost deserted except for helmeted riot police and some stragglers hoping to catch the last bus or taxi.

Citizens throughout the capital responded to an opposition call to stay at home and protest peacefully by banging empty pots and pans at their windows, on balconies and rooftops.

Tonight, downtown Santiago still echoed with the din of that protest from districts nearly a mile away.

Military officials announced at midday that no pedestrians, traffic or other movement would be allowed on the streets in Santiago during the four hours of curfew. Some nighttime traffic control, particularly after mignight, has been in effect in Chile for the past decade.

Army trucks bearing troops could be seen entering barricaded streets in the southern part of the city shortly before the curfew began.

Earlier, police attacked barricades in at least half a dozen districts of the city with water cannon and tear gas, and were pelted with stones by students and other militants.

The street demonstrations, however, were not called by the opposition organizers who appealed to citizens to avoid violence. The extent of the noisy but peaceful protest appeared to satisfy opposition hopes of continuing its movement despite the government crackdown.

The street clashes appeared to have been less widespread than during two previous national protests within the past three months.

Throughout the day, scattered bombing incidents destroyed buses and blacked out parts of Santiago and other cities. In the capital, dozens of vehicles and up to half of some bus fleets were disabled by nails left in side streets and even along the central Pan American Highway.

In the capital, which holds almost 40 percent of Chile's population of 11 million, five armed men blew up a bus this morning after forcing its passengers off. Nearby buildings were sprayed with gunfire, but no injuries were reported.

In working class neighborhoods, where five persons died during last month's national protest, police put on steel helmets and manned roadblocks this afternoon to spread news of the curfew.

The government-ordered curfew and troop deployment, which was also reportedly applied in several other major cities, were described by human rights organizations as the most severe such measure taken by the 10-year-old government since 1975.

An official statement said the move "has the acceptance of the immense majority of the country, which only aspires to live in an environment of peace and tranquility."

Politicians and diplomats had expected strong measures by the government today to prevent renewed demonstrations after two months of growing confrontation between Pinochet and an opposition led by labor unions and political parties representing the ideological center and left.

Pinochet vowed two weeks ago that no more demonstrations would be permitted, adding, "It's all over gentlemen."

Since then, the government has sought to isolate and break up the opposition's union and political leadership while offering conciliation to more moderate groups.

On Saturday, a judge ordered the jailing of Christian Democratic Party President Gabriel Valdes and two other party leaders for suspected involvement in the printing of 700,000 leaflets confiscated by police. Valdes, a former foreign minister, the party secretary, Gen. Jose de Gregorio, and former senator Jorge Lavandero remained in a city jail today and were prohibited from all outside contact.

A government crackdown on the media has blocked almost all direct reports of the protest. Following the jailing of Valdes, news media gave extensive coverage to the case and protests by a number of European and Latin American governments, but did not explain that the incriminating leaflets called for peaceful demonstrations today.

Political sources said police had confiscated 1 million leaflets in raids during the past two weeks, but that 1 million others had been printed. The leaflets specified that citizens should remain inside while banging pans, a protest made famous in Chile by opponents of the leftist government of Salvador Allende, deposed by the military in 1973.

The Christian Democratic Party, which like other political parties has been dissolved by the government under a general ban on political activity, has continued to operate and was the principal organizer of today's protest, along with the Chilean Communist Party.

The parties emerged at the front of the protest movement following a series of jailings, court actions and internal exiles imposed on labor leaders who called the protests in May and June.

The government also managed to neutralize more conservative labor associations through conciliatory measures. Following the national truckers association's effort to lead a national strike last month, government officials agreed to finance the renegotiation of $120 million in debts held by association members.

Pinochet has also signaled a political liberalization by allowing the return of eight exiled political leaders and ending censorship of books. Today's measures, however, indicated that the government intended to depend on force to stop the protest movement, diplomats and other analysts said.