FIFA has said that it is investigation the tackle on Brazilian football ace Neymar, which saw the striker ruled out of the rest of the World Cup.

Neymar fractured a vertebra in his spine during Brazil's 2-1 quarterfinal win over Colombia after being kneed by Juan Zuniga on Friday.

According to Sport24, FIFA said that it is studying the footage of the aerial challenge from Zuniga that injured Neymar's back.

FIFA Spokesperson Delia Fischer said that the governing body's Disciplinary Committee is analysing all the elements provided, the videos and the match reports, and would decide whether or not to take action.

Zuniga was rapidly being cast as Brazil's public enemy number one on Saturday but the defender insists that he had not sought to hurt Neymar in the tackle.

Zuniga damaged Neymar's third vertebra when he came rushing in from behind and kneed the Brazil forward in the back.

In a letter to Neymar and Brazilians on Saturday, Zuniga wished him a speedy recovery and insisted there was no ill will.

"I feel upset for this situation which came from a normal action in play, without ill intention, malice or imprudence on my part," he wrote.

"I want to send you a special greeting, Neymar. I admire and respect you, and consider you one of the best players in the world," Zuniga added.

"I hope you recover and are back soon to keep cheering us up in a sport full of virtues and qualities that I've always practised in my 12 years as a professional."

However, Zuniga's protests failed to impress Brazilian legend Ronaldo, who accused the Colombian of a violent attack saying that he believed there was an intention to hurt by the player.

"It was a very violent, unlawful tackle," said Ronaldo.

"We all have to fight for football to have more fair play. We have to demand that sanctions be given to violent players. I am in favour of very severe sanctions to those who don't want to play football and just want to do such violent tackles.

"It was an evil tackle," he added.