Venezuela is bracing for what Maduro's opponents vow will be the "mother of all protests" Wednesday, after two weeks of clashes between police and demonstrators protesting against moves by the leftist leader and his allies to tighten their grip on power.

The center-right opposition has called on the military -- a pillar of Maduro's power -- to turn on the president amid an economic and political crisis that has triggered severe food shortages, riots and looting.

But Defense Minister Vladimir Padrino Lopez said the army "confirms its unconditional loyalty to the president."

He made the comment before thousands of rifle-carrying members of the pro-Maduro "Bolivarian militia," who cheered with fists raised at a rally outside the presidential palace.

Maduro thanked the army and the militia for their support and announced he planned to expand the latter civilian force to half a million armed members.

"Loyalty is repaid with loyalty," he said.