CARACAS, Venezuela -- Violence erupted at an opposition rally Friday moments after its leaders said they would extend and expand a general strike aimed at unseating President Hugo Chavez. At least three people were killed and 28 others wounded, an official said.
The shootings at Plaza Francia in eastern Caracas came as diplomats worked to restart negotiations to end the strike, which has paralyzed Venezuela's oil industry and brought political tensions to a boil.
Two suspects were detained, and the state news agency Venpres quoted dissident Gen. Felix Rodriguez as saying two others remained at large.
Signaling the depth of the crisis, all seven directors of the state-owned oil company offered their resignations to company president Ali Rodriguez on Friday night, planning manager Juan Fernandez said. It was unclear whether Rodriguez, who was meeting with the managers, would accept the resignations -- or why they were offered.
Cesar Gaviria, secretary general of the Organization of American States, condemned the violence and said he would preside over an emergency meeting between government and opposition delegates late Friday.
"The acts of violence today ... take place in a moment of maximum tension," Gaviria said. "It is urgent that the negotiations team meet as soon as possible and begin producing the results that Venezuelans expect from it."
But nearly two hours after the meeting was scheduled, no government representative had arrived.
"This shows the negligence of the government," opposition delegate Eduardo Lapi said.
Three people were killed and 28 people were wounded, said Leopoldo Lopez, mayor of Caracas' Chacao district where the plaza is located.
One of those in custody, his head bloodied as police shoved him into a sport utility vehicle, told journalists he confessed to the shootings. In a brief, confused statement, he said he targeted journalists allied with the opposition.
The plaza is the main rallying point for more than 100 military officers who declared themselves in rebellion on Oct. 22, demanding that Chavez resign.
The gunfire spread panic in the plaza, filled with hundreds of citizens listening to a speech. Several bloodied people were hustled into ambulances as dissident officers appealed for calm. Protesters bundled together on the ground to protect themselves.
Police were seen hustling one man into the Four Seasons hotel, next to the plaza, as an angry mob followed. Police barred the door and the crowd tried to break it down, saying they wanted to kill the suspect.
Television stations showed one of the suspects was a young man with a buzz cut in a blue Adidas track suit. Stations showed a grainy photograph of the other, a red-haired, freckled young man with a bandage over one eye.
A motive for the shooting was not immediately known.
At a news conference, Vice President Jose Vicente Rangel pledged a "severe, strict" investigation and denounced opposition leaders for accusing the government of being behind the attack.
Some dissident officers and opposition leaders claimed that Chavez's government was responsible.
"I have no doubt that the only one responsible for this violence is Mr. Chavez. No one else is responsible," charged labor leader and general strike spokesman Carlos Ortega.
"Chavez is responsible for this crime!" dissident army Gen. Enrique Medina Gomez screamed into television cameras.
"Don't kill the people, assassin!"
Thousands of Caracas residents banged pots and pans in protest. Less than an hour after the shootings at 7 p.m. local time, several dozen people regrouped to wave Venezuelan flags and sing the national anthem.
Many feared an outbreak of political violence as the strike extended into Venezuela's crucial oil sector and street rallies intensified.
A shutdown of the oil industry raised the stakes in the strike, aimed at forcing a referendum on Chavez's presidency. Many Venezuelans accuse the populist Chavez of ruining the economy, courting communism and stirring class warfare in this deeply polarized South American nation.
The oil crisis forced the government to agree late Thursday to restart talks -- something it said it would not do until the opposition called off the strike.
Venezuela's opposition wants Chavez to call a Feb. 2 nonbinding referendum on his presidency, hoping a poor showing will increase pressure on him to resign. Chavez says the constitution allows only a binding vote in August.
Shipping agents said oil exports had stopped from Venezuela, the world's fifth-largest oil producer and a top supplier to the United States. Captains anchored tankers offshore, tugs stopped guiding ships through Venezuela's oil-rich Lake Maracaibo and dock crews stopped loading oil and natural gas.
Several refineries were shutting down in a process that takes several days. Since it no longer could fill orders, Venezuela's state oil monopoly freed buyers and sellers from fulfilling their contracts.
The government insisted that exports only were being delayed. Energy Minister Rafael Ramirez said ships in port have a five-day "window" to depart with their loads.
The export shutdown meant workers were unable to pump as many as 500,000 barrels of crude from oil fields as scheduled, Ramirez said.
The United States depends on Venezuela for more than 10 percent of its imports of crude, the raw material for heating oil and gasoline. A prolonged shutdown -- coupled with the threat of war in Iraq -- could drive U.S. energy prices sharply higher.
Hundreds of Chavez supporters attacked the newspaper El Siglo in the central city of Maracay Friday, and two employees were hospitalized with gunshot wounds, newspaper vice president Tulio Capriles said.
The U.S. Embassy denounced the "criminal aggression" against the newspaper, and Gaviria called it "an assault on freedom of expression."
An oil industry shutdown and a general strike preceded an opposition march in which 19 people were killed on April 11. Dissident officers ousted Chavez the next day.
An interim government abolished the constitution, triggering a popular rebellion. Loyalist troops restored Chavez on April 14.