Image copyright Club Natacion Cadiz Image caption Fernando Alvarez was competing in the FINA World Masters Championships

As the buzzer signalled the start of the 200 metre breaststroke final in the FINA World Masters Championships in Budapest, one competitor stood still as others raced away.

But Fernando Alvarez had not frozen, overawed by the occasion.

The veteran swimmer claims he requested a minute's silence be observed before the race, to honour the victims of the attacks in Spain that killed 15.

When that request was refused, he staged his own poignant tribute.

A video of Mr Alvarez's silent mark of respect, shared by his swimming club, Club Natacion Cadiz, has been watched over half a million times on Facebook.

In its post the club explained that Mr Alvarez had wanted to pay respect to the victims of the attacks.

Speaking to El Espanol, Mr Alvarez said he had contacted the competition's organisers on Friday, requesting a minute's silence be held, but received no reply.

He tried again on Saturday, the day of the race.

"I went to the director of the competition... but I was told that it was not possible because we could not lose a minute," Mr Alvarez said.

"It's something that has affected us all, but maybe because of the distance and because I have family there... I really think it would have been a good thing to do."

He decided to hold his own tribute.

"I stayed alone. I left a minute later. But I do not care, I felt better than if I won all the gold in the world."

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Writing on Facebook, Mr Alvarez's swimming club said they were overwhelmed by the attention that the post had received.

"In life you have to hold values above everything else," they wrote.

"It is a great example for our swimmers. All of his peers at his club feel very proud of him. We want to congratulate him for being a great person. For us he won gold."

FINA - the International Swimming Federation, which staged the championships - has faced criticism from social media users, with many people taking to the organisation's Facebook page to voice their concerns.

"Shameful not to keep a minute of silence," one social media user wrote.

"It was only one minute," another said.

FINA has been approached for comment.