CARACAS, Venezuela, Aug. 16 - The wide streets and white-washed houses in this city's affluent east end are deceptively calm, with tropical birds and lush mango trees providing a country feel just minutes from the chaotic downtown.
But here in the Sorocaima neighborhood, residents are preparing for the worst: a possibly violent confrontation between the multitudes of poor who support the country's mercurial president, Hugo Chávez, and his increasingly restive opponents. Taking precautions, the neighborhood's people have put up razor wire and electrified fences, set up citizen patrols, erected street barricades and purchased arms.
"We are worried that in a state of desperation, the government will call for a riot," explained Bruno Scheuren, 58, a publicist who, like virtually everyone in this part of the city, opposes Mr. Chávez. "Many people are afraid."
Four months after Mr. Chávez was briefly ousted in a violent uprising, trouble is stirring again as Venezuelan society has grown more polarized, and both the president's supporters and his adversaries talk of looming conflict. Although the president and his foes had vowed to reconcile after he returned to power, two days after his ouster, efforts at dialogue have faltered.
Now, a once-fragmented opposition is starting to meld into a coherent front and is embarking on new efforts to remove Mr. Chávez from office. They include pushing for a national referendum on his presidency in August 2003, and demanding criminal charges against him in the deaths of civilian protesters in the April 11 street disturbances that led to his temporary downfall.
But some of Mr. Chávez's opponents now speak privately of another uprising to topple a leader they accuse of dividing Venezuela with his left-leaning policies and confrontational manner. His supporters, mostly impoverished Venezuelans who say he has given them a voice they never had, vow to use force in his defense.
The situation is increasingly worrisome to the United States, which depends on Venezuela for 1.5 million barrels of oil a day. Bush administration officials said that unless the two sides renewed talks soon, Venezuela could spiral into violence.
"Unless there is a meaningful national dialogue, and unless that dialogue starts really soon, then there is a very good chance Venezuela will blow again," said an administration official who follows events in Venezuela.
The upheaval in April was followed by days of soul searching. Mr. Chávez apologized for his often incendiary language and promised to open talks with opponents. His foes, ranging from Venezuela's largest labor union to its biggest business association, promised to listen.
Mr. Chávez soon took some steps that were welcomed by the business class. He appointed a new economic team, replaced the president of the state-owned oil company who was seen as his crony, and pledged that the National Assembly would reconsider several economic laws opposed by entrepreneurs.
But opponents now charge that the government's actions have been half-hearted. A presidential committee set up to advance the talks has largely dissolved, with key opposition figures dropping out, saying their complaints were not heard. The opposition also charged that Mr. Chávez had continued to adopt policies that hamper business and the state oil company.
"The game is over because the president says one thing and does another," Carlos Fernández, president of the country's largest business association, Fedecámaras, said, referring to the talks. "The president in the last few weeks is back to his old self."
To many opposition lawmakers and business leaders, the only option now is to remove Mr. Chávez, a process they acknowledge could lead to violence.
"I have no doubt we could enter into a civil war, a fight between brothers," said Gerardo Blyde, a member of the National Assembly and a Chávez foe. "We have all the ingredients for that war: intolerance, sectarianism, exclusion and the incompetence to resolve the problems."
To strengthen its efforts, the disjointed opposition formed, in June, a group called the Democratic Coordinator. Though its members include the once powerful Democratic Action Party, Fedecámaras, and representatives of labor and the Communist Red Flag Party, it is united behind the goal of ousting Mr. Chávez.
With the advice of lawyers and public relations experts, the group has embarked on a legal effort to cut short Mr. Chávez's presidency. The main strategy is to prod the Supreme Court into investigating him for the deaths of the 18 people in the April protests and for what they call mismanagement of public funds.
The president's foes were emboldened when the Supreme Court on Wednesday dismissed charges against four military officers the government had accused of rebelling against Mr. Chávez in April.
The two sides have not ruled out negotiations. In recent days, both the government and the opposition extended invitations for the Carter Center, former president Jimmy Carter's Georgia-based group, the Organization of American States and the United Nations to choose a representative to help open talks.
But an effort by Mr. Carter to broker talks between Mr. Chávez and his opposition during a visit last month ended when the opposition refused to meet him. Foreign observers who closely follow events here say the acrimony on both sides has weakened the possibility for fruitful talks.
Indeed, Mr. Chávez and his supporters see many of his opponents as mere coup plotters, while opponents often speak of Mr. Chávez as a fascist or lunatic.
"It's polarized to the extent of mutual contempt bordering on hatred, so you have people who refuse to even talk to other people," said a Western diplomat in Caracas.
Some members of the Democratic Coordinator continue to hold out in private the possibility of a coup by officers of a still-restless military.
"There is an inclination toward a way out of any kind," said one official in the group.
Other opposition leaders say a better option is a campaign of street protests to so debilitate Mr. Chávez that he would resign.
"The strategy is to encircle Chávez to the point where he leaves, or he is tried on charges or he goes under some other scenario," said Carlos Hermoso, a leader in the Red Flag.
To the president's ardent supporters, such plans are nothing short of treason and must be met with force.
"They insist on conspiring, in taking out President Chávez and establishing their own government," said Désirée Santos, a close ally in the National Assembly. "We would not permit a government without Chávez."