REPORT: After month of protests, Venezuela's Maduro triggers shakeup of powers

Venezuela's socialist President Nicolas Maduro announced on Monday the creation of a new popular assembly with the ability to re-write the constitution, which foes decried as a power-grab to stifle weeks of anti-government unrest.

"I don't want a civil war," Maduro told a May Day rally of supporters in downtown Caracas while elsewhere across the city security forces fired tear gas at youths hurling stones and petrol bombs after opposition marches were blocked.

Maduro, 54, has triggered an article of the constitution that creates a super-body known as a "constituent assembly."

It can dissolve public powers and call general elections, echoing a previous assembly created by his predecessor Hugo Chavez in 1999 soon after he won office in the South American OPEC nation.

"I convoke the original constituent power to achieve the peace needed by the Republic, defeat the fascist coup, and let the sovereign people impose peace, harmony and true national dialogue," Maduro told red-shirted supporters.

Only half of the 500-member assembly, or less, would be elected and political parties would not participate, he said.

Opponents fear Maduro would stuff the assembly with supporters and manipulate the elected seats by giving extra weight to pro-government workers and unions.

They said it was another attempt to sideline the current opposition-led National Assembly and potentially avoid elections amid a bruising recession and protests that have led to 29 deaths in the last month.

The opposition had been demanding general elections to try and end the socialists' 18-year rule. A grave-faced National Assembly President Julio Borges on Monday evening called on Venezuelans to rebel, potentially portending bigger protests.

"This is a scam to deceive the Venezuelan people with a mechanism that is nothing more than a coup," Borges said, urging Venezuelans to block streets early on Tuesday and hold another march on Wednesday. Opposition supporters on Monday night were also banging empty pots and pans from their windows in a traditional Latin American form of protest.

Since anti-Maduro unrest began in early April, more than 400 people have been injured and hundreds more arrested.

While Maduro alleges a U.S.-backed coup plot, foes say he has wrecked the economy and become a tyrant.