About 100 supporters of Leopoldo Lopez, the jailed Venezuelan opposition politician, have rallied outside a Caracas court where he had been due to hear charges blaming him for a deadly episode of violence.
But his party said in a Twitter message on Wednesday that the hearing had been moved to a military jail.
Juan Carlos Gutiérrez , Lopez's defence attorney, said a court illegally ordered the change claiming it would protect Lopez's life.
Heavy security had surrounded the Palace of Justice, blocking streets leading to the building, where Lopez, a Harvard-educated economist, had been scheduled to appear after spending the night at the Ramo Verde jail in Caracas.
Al Jazeera's Rachel Levin, reporting from the Venezuelan capital, said: "The government has issued a new statement saying that the hearing will be held in the prison where Lopez is kept right now.
"However, Lopez's lawyers say that having him appear in that prison for his hearing is putting undue stress on him and they are arguing against it.
"But the government says it is doing it for the safety of Lopez. It claims there is a plot against him from his own party."
Lopez's surrender to National Guard troops at a protest rally on Tuesday came after two weeks of protests against the leftist government of President Nicolas Maduro.
College student dead
Four people have been killed in violence linked to the ongoing protests, as sporadic trouble was reported across Venezuela again on Wednesday.
The latest fatality was a 21-year-old woman who had suffered a bullet wound to the head during a march in the city of Valencia.
Genesis Carmona, a college student and model, died in a clinic later on Wednesday.
In western Tachira state, security forces and protesters fought in the streets for about two hours, with two students injured, various vehicles damaged or destroyed, and local monuments charred, witnesses said.
In southern Puerto Ordaz city, pro- and anti-government marchers fought in the street, witnesses said, with police firing tear-gas to quell the trouble.
Three government supporters were injured in the melee when shots were fired, and both sides faced off with sticks and stones, the witnesses said.
Maduro, successor to the late Hugo Chavez, is under fire over what critics say is rampant crime, runaway inflation, high unemployment and other economic problems.
After three people were killed in street clashes on February 12, Maduro ordered Lopez's arrest, blaming him for the violence.
Lopez told thousands of his supporters, all clad in white, on Tuesday that he hoped his arrest would highlight the "unjust justice" in Venezuela.
Draped in a Venezuelan flag, Lopez emerged in the crowd on Caracas's Plaza Brion, climbing a statue of Cuban independence hero Jose Marti.
"I present myself before an unjust justice, before a corrupt justice," he said.
"If my incarceration serves to wake up people... it will have been worth it."
Lopez walked under escort to a National Guard vehicle as his supporters pressed around the vehicle, blocking its path.
On the same day, Maduro, speaking to pro-government oil workers dressed in red in the western part of Caracas, countered that Lopez would have to "answer for his calls to sedition".
Maduro ordered the expulsion of three US diplomats on Sunday, accusing them of meeting student leaders under the guise of offering them visas.