In a speech delivered last night from Simón Bolívar Room of Miraflores Palace (Government House), Maduro said that Washington gave the green light and the approval for a coup process against Venezuela. "A couple of motorcyclists, both wearing red, shot to the crowd and hit the boy", said the witness, who requested anonymity.

The Information Ministry did not immediately respond to an email seeking comment.

The "mother of all marches" kicked off at 10 a.m. ET from 26 designated points of Caracas, with the goal of meeting up at the Ombudsman's Office to demand full respect for the opposition-controlled Parliament and an electoral timetable to replace the embattled President Nicolas Maduro.

In the statement in question, written by Toner and titled "Non-Violence and Accountability During Protests in Venezuela" the US government urged "demonstrators to express themselves non-violently" and also reminded the Venezuelan police and other forces "of their legal and constitutional responsibilities to protect, not prevent, peaceful demonstrations".

Maduro's opponents are vowing to stage the "mother of all protests" calling for his ouster, after two weeks of violent demonstrations that have left five people dead and dozens wounded. Youths throwing rocks have squared off against security forces spraying tear gas in melees that have dragged on well into the evening.

Top officials claim the boy was assaulted while walking home from a soccer game, but the director of Hospital Clinicas Caracas where the teen was taken told Fox News there was no doubt the boy came from a rally concentration in western Caracas.

Julio Borges, center, president of the National Assembly and deputy of the Venezuelan coalition of opposition parties (MUD), tears a copy of a sentence of the Venezuela's Supreme Court during a news conference in Caracas, Venezuela, March 30, 2017.

Protestors are demanding new presidential elections and the release of jailed opposition politicians with the backdrop of worsening economic conditions and a social crisis.

What Are Snap Elections? What to Know Ahead of June 8
Polls suggest the ruling Conservative Party stands to significantly expand its slim, 17-seat majority in the House of Commons. Liberal Democrat leader Tim Farron said that broadcasters should hold debates anyway, with an empty chair in May's place.

Venezuelan media outlets and reporters confirmed that one young man died after being shot in the head at a protest in San Bernardino, although the details of his death are not yet known. But it had the added effect of energizing Venezuela's fractious opposition, which had been struggling to channel growing disgust with Maduro over widespread food shortages, triple-digit inflation and rampant crime.

A demonstrator walks along a barricade set up during opposition.

Marchers in the opposition demonstration in Caracas included Liliana Machuca, who earns about $20 a month holding two jobs teaching literature. Although she doesn't expect change overnight, she said protesting is the only option the opposition has against an entrenched, increasingly repressive government.

She says: "This is like a chess game and each side is moving whatever pieces they can. we'll see who tires out first".

Many were state workers like Leidy Marquez, who was bused in from Tachira state, on the other side of the country, along with co-workers at state-run oil giant PDVSA.

Venezuelan President Nicolas Maduro has accused the U.S. State Department of encouraging Venezuelan opponents to attempting a government overthrow. He also said authorities in recent hours had rounded up unnamed members of an underground cell of conspirators at Caracas hotels, including some who were allegedly planning to stir up violence at the march. We are going to fight and confront the coup plotters, and we are going to defeat them with the people and the Armed Forces united, and the Constitution in the hand, ' he said.

Maduro said this week that he would increase the size of a citizen militia that supports the government to 500,000 members and give each cadet a gun. There's also criticism that the government isn't doing enough to restrain the collectives - motorcycle-driving militants - that have operated like shock troops firing on protesters as security forces stand by.

"Those responsible for the criminal repression of peaceful democratic activity, for the undermining of democratic institutions and practices, and for gross violations of human rights, will be held individually accountable for their actions by the Venezuelan people and their institutions, as well as by the worldwide community", the U.S. State Department said in a statement Tuesday.