More than 300 have been injured after a pier collapsed into the sea during an urban music festival in Spain.

At least five are said to be in a serious condition having suffered broken arms or legs and head injuries after the wooden structure gave way during the 'O Marisquiño' event in Vigo on's northwest coast.

Local media said the pier collapsed moments after rapper Rels B had told revellers to jump at the beginning of his set.

There were scenes of panic as people tumbled into the sea and fell on top of each other in a domino-like effect.

More than 300 have been injured after a pier collapsed into the sea during a music festival in Spain amid reports it happened moments after a rapper told the crowd to jump

There were chaotic scenes as revellers scrambled to rescue those who had fallen into the sea (left). Right: A man stands on concrete supports after the wooden pier collapsed

More than 300 were injured - five of them seriously - when the structure gave way overnight

Dramatic pictures show how a huge section of the pier gave way to the left of the festival stage

There were scenes of panic as revellers slipped into the water following the terrifying pier collapse. It happened during a performance by the rapper Rels B

Police said they had no record of any 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.

Festival-goer Aitana Alonso told local paper Diario de Vigo: 'The floor gave way beneath us as if we were in a lift. It was a question of five seconds. The platform broke and we all fell.

'People landed on top of me. I tried to get out and couldn't. My foot ended up stuck in the water but I managed to free it before a boy gave me his hand and pulled me out.

'There were people underneath me, shouting they couldn't get out. I didn't think I would.'

Photos have emerged on social media showing the panic that set in moments after the collapse

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

At least five are said to be in a serious condition following the freak accident at midnight in Vigo on Spain 's northwest coast having suffered broken arms or legs and head injuries, officials say

The structure collapsed during the 'O Marisquiño' urban music festival virtually as the clock struck 12am last night

There have been no reports of fatalities despite revellers tumbling into the sea when the pier collapsed beneath them

Aftermath: One frightened reveller described the scene last night as 'horrible, chaos, panic'

A friend described the scene as 'horrible, chaos, panic', adding: 'I saw a family and the little girl was saying to her dad, 'If we die here, I love you.'

'It was the worst moment of my life,' said one of the concert goers who reported seeing people screaming and running around.

Another 16-year-old 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 now be launched to determine why the wooden platform collapsed.

Police said they had no record of any 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

There were no immediate report of any Britons or Irish among the casualties, although the nationalities of those hurt has not yet been revealed

City mayor Abel Caballero (pictured) has announced an investigation will now be launched to determine why the wooden platform collapsed

Vigo's Port Authority president Enrique Lopez Veiga said he thought it was due to 'excess weight.'

There were no immediate report of any Britons or Irish among the casualties, although the nationalities of those hurt has not yet been revealed.

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.

In a tweet, rap artist Rels B wished 'strength' to the injured and advised anyone worried about friends or relatives to contact an emergency information point set up by festival organisers.