Armed motorcyclists launched an attack on a confrontation between anti-government demonstrators and police in the Venezuelan capital Caracas on Wednesday, setting off a stampede by firing into the crowds.

Two people were killed in the attack, which President Nicolas Maduro blamed squarely on fascist groups conspiring to overthrow his government.

He said he had ordered security forces to protect major cities and block any actions to destabilise the country.

“Whoever goes out to provoke violence without a permit to demonstrate will be detained,” Mr Maduro said.

The two dead were anti-government student protester Bassil Da Costa and the leader of the pro-government January 23 Collective.

National Assembly President Diosdado Cabello said the “revolutionary” known by his nickname Juancho had been “vilely assassinated by the fascists.”

About two dozen people were injured during the clashes and were being treated at local hospitals, said human rights group Provea spokesman Inti Rodriguez.

But Mr Maduro’s warnings showed no signs of deterring hard-line opposition leaders, who in a late-night news conference vowed to remain on the streets.

Extreme rightwingers within the opposition are conducting a campaign called La Salida — The Ousting to remove Mr Maduro’s democratically elected government before his mandate ends in 2019.

Opposition figures such as Leopoldo Lopez — a campaign manager for failed right-wing presidential candidate Henrique Capriles — and María Corina Machado — a signatory of the 2002 coup declaration — have called on theirs supporters to take to the streets to force the government out.