Cape Town - The two participants who tragically lost their lives during Sunday's IRONMAN African Championship at Nelson Mandela Bay’s Hobie Beach, have been named.

They have been identified as 63-year-old Leon Stanvliet from George and 58-year-old Andre Trichardt from Durban.

Police confirmed that the event organisers and police had informed their next-of-kin.

Officials on the scene said it appeared Stanvliet had convulsions during the swim and Trichardt is believed to have had a heart-related problem.

The opening swim leg at the event, normally 3.8km in length had been shortened to 1.6km due to the conditions.

Both were taken out of the water by rescuers, but attempts to resuscitate them failed.

Police spokesperson Colonel Priscilla Naidu confirmed that both incidents happened about 10 minutes apart and that both were declared dead when they reached the hospital.

“A post-mortem will be conducted to determine the exact cause of death,” Naidu confirmed.

IRONMAN South Africa released a statement confirming the deaths.

"It is with great sadness that we confirm the death of two race participants at the IRONMAN African Championship.

Both athletes required medical attention during the swim portion of Sunday’s race and were transported to a nearby hospital where they were treated. 

Our condolences go out to the family and friends of both athletes, whom we will continue to support.

We are working with the local authorities to gather all details and will continue to do everything possible to provide a safe environment for our athletes.  In respect of each family’s privacy, we will have no further comment at this time."

It is with great sadness that we confirm the death of two race participants at the IRONMAN African Championship. Both athletes required medical attention during the swim portion of Sunday’s race and were... https://t.co/968CQXBKzQ

— IRONMAN South Africa (@IMSouthAfrica) April 7, 2019