An urban music festival in Vigo, Spain ended in disaster after rapper Rels B reportedly asked the crowd to jump on the wooden pier structure.

The event, called ‘O Marisquiño’, saw crowds topple onto each other in a domino effect and into the sea.

Reports of broken arms and legs, as well as head injuries have been documented.

The chaos occurred at 12am on Sunday, at the beginning of the rapper’s set. He later tweeted out calls for strength after the incident, advising anyone worried about friends or relatives to contact an emergency information point set up by festival organisers.

A 16-year-old attendee said: “We were on the walkway when it opened up. I fell on people and people fell on me. I was hit on the head and then some sort of container fell as well. I tried to get out and someone helped me.”

City mayor Abel Caballero has announced an investigation will be launched into the platform collapse.

Police said there were no fatalities, but divers went into the sea to make sure there were no bodies.

Firemen also used thermal cameras to scan the wreckage for anyone trapped. Those who were saved from the fall helped the injured right away.

Members of the National Police, the Local Police and other emergency personnel immediately helped the injured with a succession of ambulances arriving on the scene. The injured were taken to various hospitals.

Organisers set up an information point for worried relatives who couldn’t initially find their loved ones.