Violence has broken out between police and anti-government protesters as both supporters and opponents of Nicolas Maduro, Venezuela's president, staged duelling rallies in the capital Caracas.
Protesters hurled stones and police officers fired tear gas in the latest wave of demonstrations that have so far left three people dead, AFP news agency reported.
Most were students, who have spearheaded nearly two weeks of protests against Maduro. Rampant crime, soaring inflation and basic goods shortages are their main grievances.
The latest trouble flared after thousands of Maduro supporters had earlier flooded the centre of the capital to call for peace and make a show of political strength.
In a repeat of daily confrontations this week, the students threw objects and taunted the police, who responded with volleys of teargas and a water cannon truck, or "whale" as Venezuelans call it.
'Turn yourself in coward'
Maduro said on Saturday that a police manhunt was underway for Leopoldo Lopez, the hardline opposition leader who he said was behind the anti-government demonstrations.
Lopez "ordered all these violent kids, which he trained, to destroy the prosecutor's office and half of Caracas and then goes into hiding," the president told thousands of supporters at a rally in Caracas to denounce what he called a US-backed, "fascist" plot to oust him from power. "Turn yourself in coward."
In a statement on Saturday, John Kerry, the US Secretary of State, said: "We are alarmed by reports that the Venezuelan government has arrested or detained scores of anti-government protestors and issued an arrest warrant for opposition leader Leopoldo Lopez. These actions have a chilling effect on citizens' rights to express their grievances peacefully."
'Rules for television'
Two anti-government protesters died in a rally on Wednesday, as did a pro-Maduro demonstrator in violence that saw about 60 people injured and 100 arrested.
Seeking to quell the unrest, Maduro late on Friday announced a 10-point plan to crack down on crime that includes disarming the population, increased police patrols, as well as unspecified "clear rules for television."
The protesters have demanded that Maduro step down, although opposition leaders have said that political conditions are not favourable at present for the president's exit.
Despite having the world's largest proven reserves of crude oil, the country has severe economic problems and a deep divide between rich and poor.