LA PAZ, Bolivia, Oct. 12 — Five people were killed in violent clashes with the military here on Sunday after President Gonzalo Sánchez de Lozada accused his opponents of provoking chaos in order to drive him from office. He ordered troops backed by tanks into the streets to quell mounting popular discontent and street violence.

A spokesman for the president, Mauricio Antezana, announced the troop mobilization at a news conference late Saturday night and said it was meant to retake control of El Alto, a suburb of the capital that has been the focal point of a general strike in recent days. The government, he added, "is no longer willing to tolerate the situation of violence" in that city, most of whose residents are peasant migrants of Indian origins. The president stopped short of decreeing a state of siege, which has sometimes been used to control social unrest in Bolivia.

The antigovernment protests began in mid-September and have expanded with the support of labor unions and student and indigenous groups. Mr. Antezana blamed Evo Morales, leader of the country's coca growers' union and a former presidential candidate, for the worsening disturbances, calling him the leader of "a seditious process of a coup d'état" that includes "military-style attacks on strategic objectives."

In an interview on Sunday with a local radio station, Mr. Morales denied the accusations and said the president was seeking to justify a coup of his own "so as to be able to shut down Congress." But Mr. Morales, who finished a close second in the presidential election last year, as the candidate of the Movement Toward Socialism, also said coca growers would set up roadblocks intended to cut the main east-west highway, beginning Monday.

Mr. Sánchez de Lozada, an American ally, took office in August 2002 after winning only 22.46 percent of the vote. Since then, his government has been severely hampered by quarrels within a fragile multiparty coalition, by the unwillingness of opposition groups to support legislation he favors and by a police rebellion.

The immediate cause of the unrest is a proposal to export natural gas to the United States via a pipeline that would run to a port in Chile. Opponents say Bolivians would benefit more if the gas were used for industrial development here, but they also strongly object to any role in the project for Chile, a traditional enemy.

As a result of the protests, in which at least five people had been killed before Sunday, highways around the country are being blocked by peasants and miners armed with sticks of dynamite, and normal commerce has been all but strangled. Here in the capital, gasoline is becoming so scarce that many bus and taxi companies have suspended service.

"The fishermen can't get their trout to market, and the farmers are having to watch their fruits and vegetables rot as they sit at the roadblocks," said Mario Vallejos, a long-distance hauler. "These are poor people, and they are all going broke, so everyone is angry."