MANAGUA, NICARAGUA, JULY 10 -- As gunfire crackled in the streets for a second straight day, Managua was a city in shock today, reeling from the aftermath of its bloodiest political violence in 11 years and policed by troops whose efforts to restore order achieved mixed results.

President Violeta Chamorro late Monday ordered the army and police to open up blocked streets and dislodge striking government workers supported by the opposition Sandinista Front from government offices and state-owned businesses.

Bulldozers manned by army troops knocked down the paving-block barricades, but some were promptly rebuilt by Sandinistas, who vowed to continue the general strike, now in its second week, that has paralyzed the capital. Police reported 12 arrests.

Although the Sandinistas still play a large role in the army and the police, they appear to be responding to the government's orders. Many supporters of Chamorro said, though, that they distrusted the security forces.

Despite continuing clashes, the violence that gripped the streets Monday seemed to ease today, with casualty counts declining. Hospitals contacted by telephone reported four dead and at least 70 injured in the two days of violence. A fifth man was killed Friday in what police said was an incident related to the strike.

Following an afternoon lull, however, the fighting appeared to resume late in the day, and at nightfall a fierce battle raged around Radio Corporation, the main pro-government station. The station announced that there were injuries from gunshots, but it was not clear how many.

The National Workers' Front, supported by the Sandinista party, has demanded that the government agree to direct negotiations on a host of economic and political issues that are central to Chamorro's plan to revitalize and restructure Nicaragua's economy, one of the poorest in Latin America. Chamorro has offered a "broad national dialogue" but stopped short of agreeing to direct talks with the strikers.

The presidents of Guatemala, El Salvador, Costa Rica and Honduras issued a joint communique Tuesday "calling on the international community to lend its valuable assistance to the Nicaraguan government in its search for a solution to the crisis it is undergoing," the Associated Press reported.

The general strike, which began eight days ago, escalated steadily before erupting in violence Monday. It has stopped work in government offices and state-run industries, interrupted banking, electrical, mail, telephone, bus and other services and closed the international airport.

Diplomats said the strike threatened to cripple Chamorro's economic recovery program even before it got off the ground. The plan is based on increasing agricultural production, cutting the public payroll and luring foreign investment.

Agricultural output, particularly of cotton, the primary crop, has already been hurt by striking workers. Job security for government workers is a key demand of the strikers. And the events of the last two days could discourage significant foreign investment.

"No matter who looks like the winner at the end of this, Nicaragua's chances for recovery are badly hurt," said a diplomat. "Nicaragua is the loser."

Since noon Monday, the streets around the station have been the scene of at least four confrontations, including incidents involving police and troops. Three olive-green army jeeps, parked across from the station, had been seized from troops who had entered the neighborhood, partisans said.

This morning, dozens of young men, some of them armed with pistols and AK-47 assault rifles and others carrying stones or molotov cocktails, milled about the neighborhood, vowing to fight to the death to keep the station operating.

Inside Radio Corporation, a stuffy room next to the broadcast studio had been transformed into an operating room, staffed by volunteer doctors and nurses and equipped with surgical equipment donated from local pharmacies.

The doctors said 16 victims, including 10 with gunshot wounds, had been treated there since Monday morning. As they spoke, a young man with a bullet wound in the groin was rushed into the room and laid on a bench, unconscious.

Many hard-line government supporters, who gathered in angry groups at intersections and near work sites, said the only solution was armed intervention by the United States or the United Nations.

"The police, the army -- they're all the same Sandinistas," said Felix Escorcia, 36, a bus driver who stood in a knot of men denouncing the Sandinistas near the city's main bus depot. Bus service has been halted by the barricades, several of which have been erected within a few hundred yards of the depot. "What we need is a cleansing in the form of an intervention by the Marines."

Another man in the group, Roberto Sovalbarro, 30, a contractor, was shouted down when he suggested to a reporter that U.S. intervention would only worsen the situation. "There should be a dialogue, not a war," he said.