At least one person has been killed and dozens hurt since the protests began on Friday. Troops sporadically have inundated rock-throwing protesters with tear gas to stop what government officials call "terrorist" acts.
"Their only aim is taking power through violence," declared Information Minister Jesse Chacon.
Chacon ruled out martial law to crack down on the protests. He insisted the government would regain control of the streets "little by little."
Opposition leaders called the disobedience campaign to demand that election officials should approve a presidential recall petition presented in December.
The National Elections Council is deciding on the authenticity of more than 3.4 million signatures opponents say they turned in to demand the vote.
The council postponed a decision on Sunday after street clashes, but was expected to formally declare hundreds of thousands of citizens need to verify they signed the petition - a process that would further delay any recall.
"People know that if they don't fight now for the referendum the winter of an authoritarian government will be very long," said opposition leader Leopoldo Lopez, mayor of Caracas' Chacao district, where many protests have occurred.
Chavez vows not 'one drop' of oil
would US if it invaded Venezuela
Venezuela's elections council plans to reject up to 400,000 signatures outright and force more than 700,000 citizens to confirm they signed, sources involved in the verification process said.
If the citizens don't come forward, the petition would fall short of the 2.4 million signatures needed to force the referendum.
In a speech punctuated with expletives Sunday, Chavez railed against US intervention in Venezuelan politics and insulted US President George Bush as he rallied more than 100,000 supporters in Caracas.
The leftist leader accused the United States of backing a failed 2002 coup and of funding groups seeking the recall vote. He vowed "not one drop" of Venezuelan oil would reach the United States if it ever invaded or blockaded the South American country. Venezuela provides about 15% of US oil imports.
One person has already died
in the violent clashes with police
"This is to say no to Yankee intervention!" Chavez bellowed. "I'm challenging Mr. Bush to a bet. Who will last longer: Him in the White House or me?"
Washington denies backing attempts to oust Chavez.
Venezuela is torn between those who accuse Chavez of trying to impose Cuba-style communism and those who say he has given the poor an unprecedented say in politics. Chavez's six-year term ends in 2007.
Gunfire from unknown sources wounded at least nine people on Sunday as troops fought pitched battles with protesters in several Caracas neighbourhoods, according to the mayors of those districts.
On Friday, one person died and 69 others were injured, 10 from gunfire.