More than 300 people were reportedly injured on Sunday night after a wooden pier collapsed during a music festival in Spain.

Five people were left seriously hurt after the 30- metre-high wooden platform gave way at the O Marisquino festival in the northwestern city of Vigo, with some of them reportedly crashing into the sea.

According to Faro de Vigo news service, two of those seriously injured were children, while some affected persons suffered traumatic brain injuries although it did not specify their age or gender.

Spanish authorities have confirmed that a total of 313 people were injured in the collapse. Most of the injured have been admitted to the Alvaro Cunqueiro and Povisa hospitals, both in Vigo.

Abel Caballero, the Mayor of Vigo said the affected spectators were watching Mallorca-born rap artist, Rels B when the structure gave way just before midnight on Sunday, adding that the cause of the collapse was yet to be determined.

An unnamed 16-year-old boy who was on the promenade at the time of the collapse told Faro de Vigo: “We were all on the catwalk and suddenly everything opened, I fell on top of people and people fell on top of me.

“They hit me in the head, then a container fell, I tried to get out, someone helped me, I think. Two people, one of them is a friend of mine, were not able to get out. The container was falling on us and we were trying to hold it in.”