Riot police in Venezuela have clashed with anti-government demonstrators who were protesting against the arrest of two opposition mayors.
Hundreds of demonstrators in the Venezuelan capital, Caracas, threw stones and sticks at the police.
They responded with tear gas and water cannon.
The clashes came a day after Daniel Ceballos and Enzo Scarano were detained over their alleged role in weeks of unrest that has left 31 people dead.
The government of President Nicolas Maduro has been the target of near-daily protests over the high murder rate, skyrocketing inflation and shortages of basic goods.
He has blamed the violence on "fascist groups".
Juan Requesens, a student leader at the protest, said the two mayors were "victims of persecution, abuse, and wrongful arrest".
Another demonstrator, Eusebio Acosta, said they were marching to "rebuild democracy" in Venezuela.
"The youth today have decided they're ready to give up their lives for the country, for freedom," he continued.
Interior Minister Miguel Rodriguez tried to distance the government from the arrests.
"It's important that Venezuelans understand that the bodies of the state, in this case not the government, act to protect the right of majorities, and not the rights of a small group that wants, under the guise of the right to protest, to mar the lives of Venezuelans," he said in a televised news conference.
On Wednesday, Venezuelan intelligence agents detained Daniel Ceballos of the Popular Will party on charges of inciting violence and fostering the protests.
He is the mayor of San Cristobal, near the Colombian border, where the current wave of anti-government protests broke out six weeks ago.
He has been an outspoken critic of the tactics deployed by the security forces to police the protests, accusing them using excessive force.
The authorities also arrested Enzo Scarano, the mayor of San Diego of the opposition MUD coalition.
He was sentenced to 10 months and 15 days in prison for failing to keep protesters from barricading streets in his northern city in Carabobo state.
The opposition says the government is violently repressing the protests and trying to silence the administration's critics.
For his part, President Maduro accuses them of planning a coup against his government.
He says he has repeatedly invited them to the presidential palace for talks, but that they have refused to attend.
Earlier this week the opposition leader Henrique Capriles agreed to meet the president, but no date has so far been set for the meeting.