The yesterday's rally was also meant as a show of support for a slate of 33 magistrates -- a so-called shadow supreme court -- whose names were put forward Friday by the opposition to replace Venezuela's current high court, which is closely allied with Maduro and frequently rules in his favor.
Emboldened by a nationwide strike on Thursday that paralysed parts of the capital Caracas and other Venezuelan cities, opposition leaders held a mock swearing-in ceremony Friday for the shadow court's new "judges."
The shadow court has strong support from the demonstrators, organisers said Saturday.
"Everyone has given their backing to the new Supreme Court," tweeted Freddy Guevara, a leader of the opposition-led congress.
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"We support the new judges because they will restore independence to the Supreme Court," said 43-year-old demonstrator Luis Torrealba, marching with his wife and teenage son.
In yesterday's march, hundreds of people took to a key Caracas motorway to head downtown toward the court building. But uniformed National Guard troops riding motorcycles fired tear gas to disperse them.
"They are not going to frighten me," Arteaga said in a video he posted on Twitter. He is seen in a hospital bed with bandages on his face and swollen lips. "We are going to keep fighting."
The swearing-in of a shadow judiciary was condemned by the government as "incitement to subversion" and an act of "treason," and officials threatened to throw the dissidents into prison.
With the situation already inflamed, the stakes have risen further, after the United States threatened economic sanctions if Maduro proceeds with a controversial July 30 election of a body to rewrite the constitution.
The president has vowed to maintain the July 30 election of 545 members to the "Constitutional Assembly."
Yesterday's protests, like many others since April, were organised by the Democratic Unity Roundtable, a coalition of political opposition groups.
The number of deaths in protests across the country since April has reached 103 -- about one fatality per day.