Venezuela braced for a showdown between the military and regime opponents  at the Colombian border on Saturday, when self-declared acting president Juan Guaido has vowed humanitarian aid would enter his country despite a blockade.

Opposition chief Juan Guaido stunned the world on January 23 when he declared himself acting president of Venezuela, plunging the crisis-hit country into new turmoil.

Venezuela's political tug-of-war morphs into a battle of the bands on Friday, with dueling government and opposition pop concerts ahead of a weekend showdown over the entry of badly needed food and medical aid.

Venezuelan opposition leader Juan Guaido made plans to head for the border with Colombia to personally bring in US-supplied food and medicine in defiance of the military-backed government, raising fears of possible weekend confrontations. 

Jhonny Godoy had taken to Twitter to proclaim his opposition to President Nicolas Maduro, posting a video that showed him running through the streets waving the national flag as protests erupted across Venezuela's capital.

Two days later, his family said, rifle-wielding special police agents wearing black masks stormed into their home in the Caracas slum of La Vega, pulled him outside and shot him to death.

US President Donald Trump on Monday urged Venezuela's military to accept opposition leader Juan Guaido's amnesty offer, or stand to "lose everything," as a crisis deepened over President Nicolas Maduro's refusal to let in desperately needed humanitarian aid.

Bringing in humanitarian aid is crucial to the viability of Guaido, who has denounced Maduro's re-election last year as fraudulent and in January declared himself interim president, a move recognized by some 50 countries.

Twenty-five countries have pledged $100 million in aid to Venezuela, a top US official said Thursday, as the crisis-hit country's Supreme Court took aim at oil executives appointed by the opposition.

Venezuela's opposition leader Juan Guaido took another step Wednesday in an international bid to economically starve President Nicolas Maduro's regime, announcing the appointment of a new board for Citgo, the US-based arm of state oil firm PDVSA.

Venezuela's opposition plans more marches Tuesday to press the military to let in US humanitarian aid, which President Nicolas Maduro says is the stepping stone to an invasion.

When Jose Humberto Vivas needs to trade dollars for Venezuelan bolivars, he usually flouts the nation's rigid exchange controls by turning to illegal currency traders.

But last week, Vivas put a few hundred dollars in his wallet and headed to an exchange house regulated by Venezuela's socialist government, lured by the seemingly improbable prospect of an official rate that is more inviting than the black market rate.