A mob of supposedly armed Chavistas attacked Friday the Venezuelan legislature, which has an opposition majority, with explosives, sticks and stones, leaving four people injured and extensive material damage, the National Assembly said in a statement.

The aggressors, according to the legislature, were members of the so-called collectives - pro-government, often armed civilian organizations - who tried to knock down the main door to the building or detonated explosives and fireworks, "while most of them made threatening advances with pipes, sticks and stones."

The attacks came in response to the streets being blocked around the National Assembly by legislature workers as an anti-government demonstration, called Thursday by the MUD opposition coalition, against the killing of an anti-government protester.

Among the injured were Amalia Andrade, "who had an exposive thrown at her feet"; Urimare Capote, "who lost his hearing because of an explosion"; Argenis Hernandez, "whose foot was injured by an expolding firecracker"; and Kenny Aranguren, who "had red paint sprayed on his face."

The head of the legislature's payroll administration, Ingrid Torrealba, said that when the attacks began, the workers were also protesting against the changes in the constitution being promoted by President Nicolas Maduro.

"We were demonstrating peacefully when the thugs showed up, the killer collectives, directed and deployed by (the mayor of Libertador municipality in Caracas) Jorge Rodriguez. They were carrying guns and wearing bulletproof vests...they came to attack us with pepper spray and rockets and then to round us up and hold us in the ground floor of the administrative offices," the government worker said.

The National Assembly reported that while these incidents were going on, a contingent of the militarized Bolivarian National Guard (GNB) "did nothing to avoid the violence," despite being posted just a few meters (yards) from the legislature.

Since April 1, Venezuela has been shaken by a wave of street demonstrations - for and against the government- some of which have ended in violence, leaving 75 people dead and more than 1,000 injured, according to figures released by the Attorney General's Office.