More than 300 people have been injured after part of a pier collapsed into the sea during a music festival in northern Spain on August 12.

Aftermath footage shows a crowd surrounding the fallen structure as people try to rescue the wounded that had fallen into the sea.

Ambulances can be seen arriving at the scene moments after.

The filmer, Angel, later wrote online: ''All of a sudden we heard a strong noise and the floor fell down.

''There was a massive hole and everyone was falling into the sea.

''Lots of people were screaming and crying whilst others were trying to climb out of the hole.

''I helped a girl with a broken knee.

''Then ambulances, firefighters and police arrived at the scene.''

Police have reported that there are no fatalities and five victims of the accident are in a serious condition.

The collapse of the pier is believed to be due to a structural failure in the pillars that supported the wooden platform.