PORTO • Spain's World Cup-winning captain Iker Casillas has told his fans that he is "feeling strong" after suffering a heart attack while training with Portuguese champions Porto on Wednesday.

Hospital medical reports revealed there was an obstruction of the right coronary artery for the 37-year-old, who has won all the major honours in the game, including the 2010 World Cup and three Champions League trophies.

The goalkeeper, who has already been ruled out of playing for the remainder of Porto's season, tweeted on Wednesday: "Everything under control here, it was a big scare. Thanks a lot for all your messages and your support."

Get-well wishes poured in from the footballing community after the news broke, with Real Madrid offering "all our support" for their former captain, their second-most capped player behind striker Raul Gonzalez (741).

The Spanish national team, of which Casillas has the all-time record of 167 caps, tweeted: "All the family at the national team and the Spanish football federation are with you. Get well soon."

Cristiano Ronaldo, his former Real teammate, also posted on his Instagram page an image of the pair together with the message: "Have strength, my friend. I hope you get well soon."

One of Spain's best-known sporting personalities, "Saint Iker" came through Real's academy and spent the bulk of his career there, making 725 appearances between 1999 and 2015 before joining Porto.

Spanish sports website Don Balon claims that the heart attack was probably the result of genetic issues because it is uncommon for people under 40 to suffer from the problem.

It also said that Casillas would have to consider hanging up his boots given the chances of the issue occurring again if he continues playing top-level football.

AGENCE FRANCE-PRESSE