Street protests turned deadly Friday as police struggled in vain to separate battling supporters and opponents of President Hugo Chavez. At least two people were shot to death and 78 others injured during rioting that convulsed a capital district for hours.

A march aimed a drawing support from the military for a nationwide strike erupted in violence when several hundred supporters of the president threw rocks, bottles and fireworks at thousands of opposition marchers and police in Los Proceres park, outside Caracas' Fort Tiuna.

Police fought to keep the sides apart, firing rubber bullets and tear gas, which sent stinging white clouds drifting through the district's tree-lined avenues. The anti-Chavez marchers responded by taunting soldiers and police with chants of "murderers."

Gunfire rang out as the melee enveloped the area, which surrounding the capital's military headquarters. Protesters and police ducked behind trees and or flattened themselves on the streets.

Caracas Fire Chief Rodolfo Briceno confirmed late Friday that at least two men were shot and killed and five others were wounded. Authorities said it wasn't immediately clear who opened fire or to what side the casualties belonged.

Authorities said at least 73 other people, including seven police, were injured -- either overcome by the tear gas or hit with rocks.

The anti-Chavez marchers were demanding the release of a dissident national guard general and urging the military to support a 5-week-old strike aimed at forcing Chavez to hold a nonbinding vote on his leadership.

Col. Jose Rodrigo Pantoja, commander of the military police, said marchers weren't authorized to enter the plaza, which the government has declared a security zone -- one of eight such zones in Caracas. He said soldiers acted only after the opposition march reached the plaza.

Crouching behind an ambulance, marcher Maria Arismendy poured water over the face of her small dog while he howled. "We're peaceful, but you see what they do," she said through her tears. "We just want our country back. Chavez has ruined everything."

Vice President Jose Vicente Rangel blamed "irresponsible" march leaders for trying to enter the security zone. "They tried to break through a security barrier and that produced the clashes with security forces," Rangel told The Associated Press.

Thousands of people milled about in neighborhoods near Los Proceres as guardsmen clashed with jeering Chavez supporters, some of whom ran through a cloud of tear gas carrying an injured colleague on a stretcher.

Opposition protesters demanded the release of Gen. Carlos Alfonso Martinez, one of about 100 officers who revolted last fall. Martinez was arrested Dec. 30 without a required court order. A judge ordered his release, but he remains under house arrest.

"We will resist until the end, until we achieve the objective of getting rid of Chavez and his authoritarian regime," said Carlos Ortega, president of the nation's largest trade union.

Venezuela's opposition called a strike Dec. 2 to pressure Chavez to call a referendum on his presidency. Venezuela's constitution permits a possible binding vote halfway into Chavez's six-year term, or next August. Chavez rejects an early nonbinding ballot.

Opposition leaders blame Chavez's leftist policies for deep economic troubles and accuse him of grabbing power. The president counters the opposition wants to stage an "economic coup."

The strike has paralyzed oil production in Venezuela, the world's fifth-largest oil exporter and a top supplier to the United States. The strike has helped push international oil prices above $30 per barrel. Oil workers have defied a back-to-work order by the Supreme Court.

Talks mediated by the Organization of American States have made little progress.

The strike has forced Chavez to seek food and fuel abroad. On Friday, he discussed aid for Venezuela with an Algerian diplomat. He also met with OAS Secretary General Cesar Gaviria on the deadlocked negotiations.

Chavez said fellow Latin American leaders have told him "not to cede to (opposition) blackmail" because it could promote "destabilization campaigns" in the region. "The force of law is going to be imposed here," Chavez said, adding he saw no immediate need to declare martial law.

Chavez said Thursdsay that he would support diplomatic efforts by a "Group of Nation Friends" to help resolve the crisis.

Ali Rodriguez, president of the state-owned oil company, told the state news agency Venpres the government has purchased 250,000 barrels of gasoline from a U.S. firm and 600,000 more barrels from Russia. Venezuela also has received gasoline shipments from Brazil and Trinidad and Tobago.

The government is trying to negotiate long-term gasoline import deals with those countries, as well as Ecuador, Colombia and Mexico, to meet the domestic demand of 400,000 barrels a day.

Analysts say importing gasoline will force Chavez' government to make budget cuts and slash social spending -- a move that could weaken his support among the poor, his power base.