Venezuela's President Nicolas Maduro has pressed ahead with a plan to create a popular assembly with the ability to rewrite the constitution, drawing instant criticism from the opposition.

Maduro says the grassroots body is needed to bring peace to Venezuela, where nearly two months of anti-government protests have left more than 50 people dead, but opponents view it as a cynical tactic to buy time and avoid a general election.

At an open air rally before thousands of red-shirted supporters, Maduro on Tuesday signed a document formally establishing the terms for electing members of a "constituent assembly" that will be tasked with drafting a new constitution.

"Votes or bullets, what do the people want?" Maduro asked the crowd, presenting the proposed 540-member body as a way to defuse increasingly violent protests, which he says are part of a US-backed conspiracy to overthrow "21st Century socialism".

"Let's go to elections now!" he said, before detailing how the new assembly will be partially elected by votes at a municipal level and partially by different groups, including workers, farmers, students, and indigenous people.

READ MORE: New Venezuela clashes after man set ablaze

The head of the pro-government electoral council said on Tuesday voting for the "constituent assembly" would be held in late July.

Regional gubernatorial elections, meant to have been held last year, would take place on December 10, he added.

'Evil announcement'

The opposition-controlled National Assembly promptly rejected Maduro's plan.

"The Venezuelan people do not want a fraudulent Madurist constitution and we will not accept it," opposition leader Henrique Capriles tweeted.

Maduro's rivals fear that a new constituent assembly could rewrite rules or exclude opposition parties, making a sham of future elections that could vanquish the ruling socialists if the polls were free and fair.

"Today's decision is nothing more than an evil announcement meant to divide, distract, and confuse Venezuelans further," said Congress President Julio Borges, the opposition leader whose coalition is pushing for early elections, humanitarian aid to alleviate food and medicine shortages, and freedom for jailed activists.

"Today we've entered a new stage and that means more struggle and more street action," Borges added

A Supreme Court magistrate decried the planned assembly, saying it was "not the solution to the crisis" and called on Maduro to "think carefully" to avoid more bloodshed.

Venezuela's state prosecutor also warned that Maduro's plan also risked deepening the crisis.

WATCH: What can be done to rescue Venezuela?

The opposition is demanding elections to remove Maduro from power. They blame him for an economic crisis that has caused shortages of food, medicine and basic supplies.

Maduro accuses protesters of seeking a violent coup and says he is the victim of a US-backed capitalist conspiracy.

Hundreds of people have also been injured in the violence, around 2,700 arrested, with 1,000 still behind bars, and 335 tried in military tribunals, according to rights groups.