1202 GMT November 19, 2019
The opposition, energized by the release from jail of one of its emblematic leaders, Leopoldo Lopez, is leading the charge against the new assembly to be chosen in a July 30 election, AFP reported.
On Monday it organized a demonstration in Caracas, during which dozens of protesters and some security force personnel confronting them were injured. Unrest also spread to other cities.
On Sunday, the opposition will hold its own symbolic public vote on whether the new constitutional assembly should be established.
"This population has decided to continue the fight for liberty," one opposition lawmaker taking part, Freddy Guevara, said.
"Sunday will be the biggest act of civil disobedience in Venezuela's history."
With Maduro determined to see through the process – which critics view as a way for him to bypass the opposition-led parliament – there are fears of more violence in the streets.
Since April 1, more than 90 people have been killed during protests. The latest was a 16-year-old killed Monday in La Isabelica, a town in northern Venezuela's Carabobo state, authorities said on Twitter.
In what could be an ominous sign of violence yet to come, a candidate for Maduro's constitutional assembly was shot to death Monday in Maracay, capital of the central state of Aragua.
According to the Telesur news channel, Jose Luis Rivas, 42, was gunned down at a campaign event.
The Venezuelan president, who rules over a once flush oil-rich nation reduced to penury, has been accused by the influential Catholic Church of turning the country into a "military dictatorship."
Campaigning for Venezuela's controversial constitutional assembly is to end on July 27.
The opposition coalition has said it will not field any candidates in an election it denounces as a "fraud."
It has been bolstered by Lopez's exit on Saturday from prison, where he had been kept since 2014 on charges of inciting violence.
He is serving the rest of his 14-year sentence under home detention in the capital, although his lawyers said they are looking to have that restriction lifted too, so he is completely free.
On Sunday – the 100th day of the protest wave against Maduro – 4,000 demonstrators marched against the president, some of them wearing T-shirts with Lopez's face and carrying banners that read: "One hundred days and I continue to rebel against tyranny."