President Hugo Chavez, the former paratrooper whose leftist politics roiled this oil-rich country for three years, resigned this morning hours after military leaders seized control of the country. His resignation followed anti-government protests that left more than a dozen people dead.

An interim government headed by Pedro Carmona, leader of the country's largest business group, was sworn in at the presidential palace this afternoon in a ceremony attended by a cross section of Venezuela's civil society. Backed by the country's top generals, who will join him on the governing junta, Carmona declared Chavez's two-year-old constitution invalid, dissolved the Chavez-controlled legislature and Supreme Court, and pledged to hold new presidential and legislative elections within a year.

Venezuela's military, business and media leaders blessed the transfer of power as an expression of popular will. But Isaias Rodriguez, Chavez's attorney general, said the president's resignation was not valid since it had not been submitted to the National Assembly and did not follow constitutional guidelines.

The distinction is an important one for the United States, which pledged along with other members of the Organization of American States in September to punish governments that did not qualify as democracies. The United States declined today to characterize Chavez's forced resignation as a coup. One U.S. official said: "That is not a word we are using. We do not think that is an accurate description of what happened."

That tacit endorsement of the interim government put the United States at odds with 19 Latin American leaders gathered in Costa Rica and the most important U.S. ally in the region, Mexican President Vicente Fox, who said he would not recognize the Venezuelan government until new elections are held.

"We lament the acts of violence which have claimed human lives," the leaders said in a statement that nevertheless did not specifically refer to Chavez's ouster as a coup. "We condemn the interruption of constitutional order."

As the country quickly resumed its daily routine, Chavez remained under arrest at Fuerte Tiuna, a military compound here. Military leaders refused a request from Chavez to leave for asylum in Cuba.

Cuban President Fidel Castro has been an important ally of Chavez's. Castro has also benefited from cut-rate Venezuelan oil under Chavez's government.

Venezuelan authorities today swept the capital, Caracas, for members of Chavez's cabinet and other former administration officials. Military officials said Chavez and his aides could stand trial for allegedly playing a role in Thursday's violence that killed 14 people and wounded hundreds.

Only scattered violence was reported today, most of it occurring in provincial capitals led by pro-Chavez governors. But Chavez administration officials said the president was ousted illegally, posing a diplomatic dilemma for the United States and Latin American nations that recently pledged to punish the hemisphere's undemocratic governments with trade embargoes and other sanctions.

Venezuela is one of the leading oil suppliers to the United States, and a determination by the Organization of American States that Chavez was removed illegally could affect exports just when violence in the Middle East is shaking up global oil markets.

"It is a real setback for the hemisphere and for U.S. policy," said Arturo Valenzuela, who was President Bill Clinton's top adviser on Latin America.

Other Latin American leaders have recently lost their grips on power in the face of civil dissent. Fernando de la Rua resigned as president of Argentina late last year in the midst of economic crisis, and Alberto Fujimori of Peru abandoned his presidency in 2000 to avoid a widening corruption scandal.

Valenzuela said the situation in Caracas is different than those cases. "Congress was not consulted, there was no succession to the vice president, no constitutional continuity," he said.

The interim president, Carmona, is a 60-year-old former oil executive who studied economics in Europe. He has never shown political ambitions before, and he said today, "I did not seek out this responsibility." As head of Fedecamaras, the country's largest business group, Carmona was frequently targeted by Chavez as a proxy for the "oligarchy." The former president once called him "scrawny."

The swift turn for Chavez, elected in 1998 on a broad promise to help Venezuela's poor majority, effectively ended one of Latin America's most ardent leftist governments at a time when a populist, anti-U.S. message has found resonance in the region. He was the latest in a line of charismatic populists in this part of the world who blamed the United States for much of the region's enduring social strife and inequality.

The son of schoolteachers, Chavez was educated and spent most of his career in the military, one of the most promising paths for lower- and middle-class Venezuelans. As a young army officer frustrated by Venezuela's corrupt two-party system, he formed a group of like-minded leftist soldiers that tried to stage a coup against the government of Carlos Andres Perez in 1992. The coup failed, but Chavez made himself a household name by calling the attempt a strike against corruption.

Chavez's departure removes a leader whom the United States had long viewed as a potential threat to its interests in the Andes, now dominated by the war in neighboring Colombia. Marxist guerrillas there have intensified their campaign against the U.S.-backed Colombian government, and Chavez has refused a number of U.S. requests for help on the issue.

Since criticizing the U.S. war in Afghanistan last fall, Chavez has reached out to the United States in the hopes that restored friendship would shore up his fading popularity at home. The new U.S. ambassador to Venezuela, Charles Shapiro, has stated on several recent occasions that the United States would not support "extra-constitutional" measures to remove Chavez from power.

Those statements have come as the United States has sought his help on a number of pressing foreign policy problems in the region. Last week, Shapiro asked Chavez to allow U.S. spy planes to use Venezuelan airspace as a short cut from Caribbean bases to Colombia and to begin providing U.S. intelligence agencies with information on this country's large Arab community, according to U.S. and Venezuelan officials familiar with the conversation. Chavez did not give his answer. But in a later interview, Foreign Minister Luis Alfonso Davila said that "Venezuela does not submit to pressure."

Members of the country's diverse opposition had been visiting the U.S. Embassy here in recent weeks, hoping to enlist U.S. help in toppling Chavez. The visitors included active and retired members of the military, media leaders and opposition politicians.

"The opposition has been coming in with an assortment of 'what ifs,' " said a U.S. official familiar with the effort. "What if this happened? What if that happened? What if you held it up and looked at it sideways? To every scenario we say no. We know what a coup looks like, and we won't support it."

At the same time, opposition legislators have been brought to Washington in recent months, including at least one delegation sponsored by the International Republican Institute, an organization that promotes democracy and is affiliated with the Republican Party. Its past president, Lorne Craner, is the Bush administration's assistant secretary of state for democracy, human rights and labor.

"Last night, led by every sector of civil society, the Venezuelan people rose up to defend democracy in their country," the group's president, George A. Folsom, said in a statement. "Venezuelans were provoked into action as a result of systematic repression by the government of Hugo Chavez."

After more than two days of a national strike, several hundred thousand people descended Thursday on the presidential palace to demand Chavez's resignation. The strike began as a managerial protest at the state-run oil company, but evolved into a broad effort supported by the country's largest business and labor groups to force Chavez from power.

After the president pulled private television stations off the air, shooting started along downtown streets. Protesters blamed government snipers and pro-Chavez civic organizations known as Bolivarian Circles for firing on the crowd. Several police and intelligence agents also died in the shooting, prompting Chavez supporters to claim that the opposition started the shooting as a pretext for the military intervention.

Gregory Wilpert, 36, a sociology researcher, was making his way toward a pro-Chavez rally in the hectic downtown streets when shooting broke out along Baralt Avenue near Plaza Caracas.

He said that, although he could not identify the participants, men were firing down from a bridge over Baralt Avenue and from the tops of buildings. He said another group of men was firing back, offering a more complicated picture than the one described by opposition leaders who have claimed that pro-Chavez groups shot into defenseless crowds.

"There was a gunfight going on," Wilpert said. "There was no crowd because everyone ran away when the firing started, except for people hiding in doorways. I couldn't tell if the groups were pro- or anti-Chavez, but they were firing at each other."

Venezuelan police officers the entrances of the Miraflores presidential palace in Caracas, where protests turned violent this week.Pedro Carmona, a former oil executive appointed interim president, flashes a victory sign after taking the oath of office.