Cúcuta (Colombia) (AFP) - Arenri Roque endured three days on a bus to take in a fund-raising concert Friday for Venezuela's opposition -- one thrust of a musical duel with the government, which is staging a show of its own.

The odd battleground is the Tienditas bridge linking Venezuela with the Colombian city of Cucuta, where Roque walked around stocking up on essentials she cannot get in economically crippled Venezuela.

Police on horseback patrolled the streets as crews tested sound equipment and cameras for the mega-concert organized by British billionaire Richard Branson. 

The bill features 30-odd pop stars from the Spanish-speaking world, such as Alejandro Sanz of Spain and the Mexican rock group Mana. 

On the Venezuelan side of the span, in the town of Urena, workers raced to finish setting up a huge stage for the pro-government show.

The government has yet to say who will perform.

Cucuta is one of several places where humanitarian aid for Venezuela, much of it from the US, is being stockpiled.

President Nicolas Maduro is vehemently against letting in such assistance, saying it would be the harbinger of an invasion.  

Opposition leader and self declared interim president Juan Guaido, who was headed to the border Thursday night, has vowed to bring aid in on Saturday. He has not said how he will pull this off.

Roque, who came here with her best friend Yari, is tickled by the prospect of a concert with big-name performers that she loves, but says there is more to this event.

"It is not just a concert. Song lyrics really motivate people to transform their lives. Obviously, by transforming their lives, these people transform societies," said Roque, 33, a slight woman who has two children.

Organizers say the concert is meant to kick off a 60-day fund-raising campaign which they hope will raise $100 million for Venezuela. The country is suffering from acute shortages of basic foodstuffs and medicine and from hyperinflation that renders people's money virtually worthless.

'A lot has gone wrong'

Margaret Ocando, a 35-year-old former business administrator who now gets by selling goods on another border bridge, is hugely optimistic about the concert.

"A lot has gone wrong in Venezuela. The concert could suddenly resolve the situation," said Ocando.

She said that if nothing else, the concert will serve as a distraction from all her woes.

Lined up on the Colombian side of the bridge were trucks carrying food, personal hygiene kits and medicine sent by the US, waiting to enter Venezuela.

The span is blocked by cargo containers placed there by the Venezuelan military, the lynchpin of Maduro's support.

His government has not given much publicity to the pro-Maduro concert, which it says will last through Sunday. It is not known if Maduro himself will attend, nor who will perform.

A Venezuelan salsa singer named Willie Gonzalez, whose career peaked in the 1980s, is reported to have turned down an invitation to take part.

And will dueling concerts 300 meters apart drown each other out?

No, said sound engineer Fausto Castano on the Colombian side. That distance is enough.

"There will not be any interference," he said.