Most of the Venezuelan parliament asked the armed forces to stop "repression" in opposition demonstrations and be loyal to the Constitution

Venezuela braced for rival demonstrations Wednesday for and against President Nicolas Maduro, whose push to tighten his grip on power has triggered waves of deadly unrest that have escalated the country's political and economic crisis.

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.

Sowing fears of more violence, Maduro has in turn urged his supporters, along with the military and civilian militias, to defend the leftist "revolution" launched by his predecessor Hugo Chavez in 1999.

It is set to be the biggest day of protests since Maduro's allies tried to strip the power of the opposition-controlled legislature -- the only lever of government Maduro's camp does not hold -- and banned opposition leader Henrique Capriles from politics.

The streets of Caracas have seen running battles pitting masked protesters hurling stones and Molotov cocktails against riot police firing tear gas, rubber bullets and water cannons.

The protests have been relatively small so far, with turnout in the thousands.

But the opposition is now hoping to flood the streets with protesters, whom they are urging to remain peaceful.

They plan to march from 26 rally points toward central Caracas, a pro-Maduro bastion and the seat of government. The authorities say they will not allow the protesters into the area, where the rival rally will be held.

Maduro's camp has vowed not to be outdone by the opposition.

"The whole of Caracas will be held by the revolutionary forces," said lawmaker Diosdado Cabello, one of the president's most powerful allies.

- 'Hour of combat has arrived' -

Pressure on Maduro has increased as falling prices for Venezuela's crucial oil exports has aggravated a financial crisis, creating severe shortages of food and medicine in the state-led economy.

On Tuesday, the center-right opposition repeated its call 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," said Julio Borges, the opposition speaker in the legislature.

But the defense minister, General Vladimir Padrino Lopez, pledged the army's "unconditional loyalty," while Maduro blasted Borges for urging a "coup" against him, saying he "should be put on trial."

The president rallied his troops this week, vowing to send 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. "We are at a crucial moment in the destiny of our nation."

Maduro on Tuesday activated the "Zamora Plan" -- a military, police and civilian operation aimed at combatting a supposed coup attempt -- which the president says is being orchestrated by Venezuela's opposition and the United States.

"The Zamora Plan is a strategic and operational plan that activates the defense of the nation in case of threats to the internal order," Retired Major General Cliver Alcala told AFP.

"But its application seems to me intimidating, they want to dissuade the protests," he said.

International campaign group Human Rights Watch also said strengthening the militia was an attempt at frightening the opposition.

"We know of no other similar case in Latin America of a government arming urban militias," the group's Americas director Jose Miguel Vivanco said at a news conference in Washington.

"By that I mean delinquents, gangs that act with total impunity and intimidate citizens, with power to shoot and make arrests."

- 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.

Mark Toner, the US State Department spokesman, echoed that call in a statement Tuesday, pressing for calm and accountability during the protests.

"We again urge demonstrators to express themselves non-violently," Toner said.

"We also again remind the public forces -– members of the police, the army and the national guard -– as well as members of the judiciary, of their legal and constitutional responsibilities to protect, not prevent, peaceful demonstrations."

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