CARACAS - Clashes broke out Wednesday at massive protests against Venezuelan President Nicolas Maduro, as riot police fired tear gas to push back stone-throwing demonstrators and a young protester was shot and wounded.

Violence erupted when thousands of opposition protesters tried to march on central Caracas, a pro-government bastion where red-clad Maduro supporters were massing for a counter-demonstration. The marchers were forced back by lines of soldiers and police deployed to contain what the opposition has vowed will be the “mother of all protests.”

On the capital’s northwest side, a 17-year-old man was shot in the head and badly wounded by motorcycle-riding gunmen who also threw tear gas canisters into a crowd of protesters, witnesses told AFP. Prosecutors said they had opened an investigation.

The opposition has repeatedly accused the government of sending groups of armed thugs to attack protesters. The security forces do nothing to stop them and themselves repress peaceful protesters, opponents say.

This is the largest day of demonstrations in more than two weeks of violent protests that have left five people dead and more than 200 arrested since moves by Maduro to tighten his grip on power escalated the country’s political and economic crisis. Pressure on the leftist leader has been mounting since 2014, as falling prices for Venezuela’s crucial oil exports have aggravated an economic crisis, creating severe shortages of food and medicine in the state-led economy.

The crisis escalated on March 30, when the Supreme Court tried to take over the powers of the National Assembly, the only lever of government Maduro and his allies do not control.

The court partly backtracked after an international outcry, but the tension only increased when authorities slapped a political ban on opposition leader Henrique Capriles on April 7.

Those events have galvanized the often divided opposition in its efforts to force Maduro from power. “We have to end this dictatorship. We’re fed up. We want elections to get Maduro out, because he’s destroyed this country,” said protester Ingrid Chacon, a 54-year-old secretary.

The president in turn has urged his supporters, the military, and civilian militias to defend the socialist “revolution” launched by his predecessor Hugo Chavez in 1999.

- ‘Hour of combat’ -

The center-right opposition has called for the military - a pillar of Maduro’s power - to abandon him.

“It is the moment for the armed forces to demonstrate that they are with the constitution and with the people,” legislative speaker Julio Borges said Tuesday.

But the defense minister, General Vladimir Padrino Lopez, has pledged the army’s “unconditional loyalty,” while Maduro blasted Borges for inciting a “coup.”

The president has sought to rally his troops this week, sending the army into the streets and ordering pro-government militias to be expanded to half a million members, “each with a rifle.”

“The hour of combat has arrived,” Maduro said.

On Tuesday night he activated a military, police and civilian operation called the “Zamora Plan” aimed at combatting a supposed coup attempt - which the president says is being orchestrated by Venezuela’s opposition and the United States.

- Region on edge -

In Latin America, where other governments are increasingly alarmed by Venezuela’s instability, 11 countries including Brazil, Mexico and Chile issued a statement Monday condemning the deaths of protesters and urging the security forces to show restraint.

US State Department spokesman Mark Toner echoed that call, urging the security forces to “protect, not prevent, peaceful demonstrations.”

Maduro, speaking at a meeting with high-ranking political and military officials Tuesday, denounced that as a “green light (for) a coup.”

According to a survey by pollster Venebarometro, seven in 10 Venezuelans disapprove of Maduro, whose term does not end until 2019.