Venezuelan opposition leader Juan Guaido turned up at a star-studded concert in neighbouring Colombia which was being staged to back him in the country’s power struggle.

Thousands of Venezuelans joined migrants on the Colombian border at the concert as they sought to pressure President Nicolas Maduro into allowing the delivery of emergency food and medicine.

Guaido’s surprise appearance on Friday at the Venezuela Aid Live concert marked a new test of authority for Maduro.

Juan Guaido
Juan Guaido arrives at the Venezuela Aid Live concert (Fernando Vergara/AP)

He was greeted with shouts of: “Juan arrived! Juan arrived!” as he was met backstage by Colombian President Ivan Duque, defying orders banning him from travelling outside the country.

On the Venezuelan side of the border, government workers assembled a smaller stage for a rival, three-day Hands Off Venezuela concert being organised by Maduro.

Venezuela aid concert
Venezuelan singer Carlos Baute, with Sir Richard Branson (Fernando Vergara/AP)

Even as several million Venezuelans flee the country and those who remain struggle to find basic goods like food and antibiotics, the embattled president claims the relief effort led by Juan Guaido is a US orchestrated ploy to oust him from power.

An optimistic mood as the concert opened in the Colombian border city of Cucuta could not mask underlying tensions a day before Maduro’s opponents embark on a risky strategy to undermine him and bring in the aid being amassed for days along three of Venezuela’s borders.

Thousands of miles away, near a crossing with Brazil, a member of an indigenous tribe was killed and 12 more injured in clashes with security forces who enforced Maduro’s orders to keep out the aid.

Hours before the concert began, dozens of Venezuelans hiked across the border through high bushes on an unmarked trail. They carried ice boxes, snacks and water and whispered directions as they kept a close eye out for Venezuelan soldiers.

“This concert happens once in a lifetime,” 19-year-old Shirley Duran said. “It will be a great opportunity for so many poor people who are suffering under the heat, who are hungry, jobless. At last they’ll have something to enjoy.”

British tycoon Sir Richard Branson organised the concert, which featured dozens of Latin musicians on a giant stage on one side of a bridge.

Venezuela concert
Thousands attended the concert (Fernando Vergara/AP)

Facing it on the other side of the bridge sat a giant shipping container and tanker that Maduro’s government has placed there to prevent the delivery of US-supplied food and medical kits.

As Venezuela’s political turmoil drags on, allies of Guaido, who the US and dozens of other countries have recognised as Venezuela’s rightful leader, hope the massive concert in Cucuta will set the stage for the smooth delivery Saturday of the aid and a turning point in their quest for a transitional government.

At the concert venue, the feeling was one of collective catharsis, especially for migrants who in recent years have fled Venezuela’s economic implosion by crossing into Colombia.

Colombian singers Silvestre Dangond, left, and Maluma, right
Colombian singers Silvestre Dangond, left, and Maluma, right, sing during the concert on the Colombian side of Tienditas International Bridge (Fernando Vergara/AP)

Under a scorching sun, concertgoers waved Venezuelan flags, squirted water at each other and swayed to music by marquee artists including Argentina’s Diego Torres as well as a host of Venezuelan performers.

Reymar Perdomo, a Venezuelan street singer who rose to fame for a video which went viral showing her singing on buses in Peru, kicked off the concert with her signature song, Me Fui, Spanish for I Left, which has become the unofficial anthem of the mass exodus.

Perdomo said performing so close to the border brought back painful memories.

“A little over a year ago I crossed this border and was robbed of my luggage and all my money,” she said.

“But I know in this moment that there will be change because Venezuelans want it and they are showing it today.”

Diego Torres
Argentine singer Diego Torres performed during the concert (Fernando Vergara/AP)

Sir Richard Branson has set a goal to raise 100 million dollars (£77 million) for Venezuelans in need within 60 days.

He said he got the idea after brainstorming with Guaido and his political mentor, Leopoldo Lopez, who is under house arrest for leading protests against Maduro in 2014.

“If we can take people to space why is it so hard to take people out of poverty?” he said, opening the concert before a cheering crowd.

“We must break the impasse and end the humanitarian crisis.”