Opposition marchers who tried to move into downtown Caracas from several points clashed with security forces for several hours on Monday and are keeping the capital's main avenues blockaded.

The Francisco Fajardo Highway, which connects the eastern and western portions of the city, has remained closed since early afternoon, when the confrontation broke out between security forces and young masked demonstrators acting as "shock troops."

Although the security forces tried to break up the march and repel the demonstrators, the letter have continued to block traffic for more than two hours and have responded to the tear gas and rubber bullets used by law enforcement by hurling stones, Molotov cocktails and containers of paint, among other things.

Venezuelan authorities have justified the move to repel the marchers by saying that the demonstrators have not been given permission to protest in the western part of the city, a bastion of the ruling political ideology of Chavism, and may not impede traffic.

A stretch of Francisco de Miranda Avenue, one of the most important thoroughfares in the capital, was also taken over on Monday by anti-government demonstrators, who have remained there confronting the authorities.

Similar clashes have been occurring along Victoria Avenue, in western Caracas, and Jose Antonio Paez Avenue, which runs north-south in that same zone.

The marchers initially attempted to reach the office of Education Minister Elias Jaua in downtown Caracas, but the processions degenerated into violent confrontations after the anti-government throng came up against a cordon set up by the National Guard and the police, blocking their route.

The opposition intended to deliver a document to Jaua rejecting the National Constitutional Assembly, given that the minister heads the commission set up by President Nicolas Maduro to draft modifications to the Venezuelan Constitution.

Opposition leaders asked their supporters to resist the government's moves with a series of protests in several cities around the country, including the capital, despite the fact that it would disrupt daily activities for thousands.

"We can all get tired because we're human beings, but we have to try and persist, not desist," former opposition presidential candidate Henrique Capriles told reporters.

Capriles, the governor of Miranda state, said that "Here, the one who is delegitimizing itself with each repressive act is the government, each repressive act it undertakes strengthens the option of those of us who want change in the country."

Venezuelan First Parliamentary Vice President, opposition figure Freddy Guevara, said on Twitter that four main avenues in the capital had been shut down, adding that "where will be no normality while the dictatorship continues."

 Since April 1, Venezuela has been experiencing a wave of demonstrations both for and against the government, some of which have turned violent, leaving 37 people dead and hundreds injured.