An apology has been issued by ITU President Marisol Casado after she congratulated Jonathan Brownlee, pictured with brother Alastair, after the WTS event in Leeds ©Getty Images

International Triathlon Union (ITU) President Marisol Casado has apologised for congratulating the wrong Brownlee brother in a letter following the World Triathlon Series (WTS) in Leeds.

Alistair Brownlee won the men’s race on Sunday (June 11) in his first appearance of the WTS season.

The London 2012 and Rio 2016 gold medallist had been competing in middle and longer distance triathlon races since defending his Olympic title.

He finished the event in Leeds 14 seconds clear of his younger brother Jonathan.

However, a letter, sent by Casasdo, wrongly congratulated Jonathan for his victory at the event.

"Dear Jonathan," read the letter, which Jonathan Brownlee posted on Twitter with the caption "awkward".

"It is with great pleasure to congratulate you on your recent victory at the Columbia Threadneedle World Triathlon in Leeds.

"Your commitment and dedication applied to your training that led to your triumphant win is an inspiration not only to your fellow athletes, but to up-and-coming athletes alike.

"You showed great determination and strength to earn a well-deserved sport on the podium and you should be incredibly proud of your achievement."

Casado apologised for the mistake on Twitter, joking the error had been due to the high temperature in Spanish capital Madrid, the location of one of the ITU’s offices.

Reigning world champion Flora Duffy emerged as the winner of the women’s race in Leeds, having finished second last year.

The next WTS event is due to take place in Hamburg, with the German city due to host competition from July 15 to 16.