Former European 1,500m champion Ciara Mageean has died at the age of 34.
The two-time Olympian, who won the European title in Rome in 2024, from Portaferry, Co Down passed at 6.30am on Sunday.
Mageean announced last year that she had been diagnosed with cancer.
Her family said in a social media post that she was surrounded by her loved ones.
They said: "A beloved daughter, sister, wife, friend and inspiration to so many, she will be deeply missed."
Mageean represented Ireland at the 2016 and 2020 Olympics, in addition to holding a number of Irish records.
She became the first individual Irish European champion since Sonia O'Sullivan when she struck gold at the 2024 championships in Rome but was unable to compete in the 2024 Olympics due to an Achilles injury.
Mageean announced her diagnosis of stage 4 bowel cancer the following year.
She went on to marry her partner Thomas Moran in October just weeks before her death.
Taoiseach Micheal Martin said he was deeply saddened by the news.
"My heartfelt sympathies go to her husband Thomas, all her family and friends," he said in a statement on the social media network X.
Tanaiste Simon Harris described the news as heartbreaking.
He said on X: "She was a European champion, two-time Olympian, a proud Irish athlete and an extraordinary person."
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Northern Ireland's First Minister Michelle O'Neill said Mageean demonstrated "extraordinary talent, determination and dedication".
"From representing Ireland at two Olympic Games to winning European Championship gold in Rome in 2024, Ciara demonstrated extraordinary talent, determination and dedication," she said.
"However, beyond the medals, records and sporting accolades, Ciara will be remembered for her warmth, courage and tremendous strength of character.
"Throughout her illness, she showed a remarkable spirit and an incredible ability to find hope and joy in life, even in the most difficult circumstances. Her courage touched countless people and will leave a lasting legacy.
"For a community like Portaferry, this loss will be deeply felt. Ciara was one of our own, and the pride she brought to her community and beyond will never be forgotten."
A statement from Athletics Ireland read: "Ciara was a much-loved and inspirational figure who touched the lives of so many. Her courage, warmth and spirit will leave a lasting legacy."
(c) Sky News 2026: Ciara Mageean: Former European 1,500m champion dies at age of 34
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