Portugal's Olympic Committee has confirmed two of its Olympians have suffered gastrointestinal infections due to sub-standard water conditions in the Seine. The most famous river in France has been the source of major controversy this summer after numerous athletes became ill due to exposure.

Some athletes competing in the 10-kilometre marathon and triathlon events had been subject to bouts of vomiting after competing. And Portugal's governing body has confirmed two of its stars, Vasco Vilaca and Melanie Santos, are now suffering from more serious illness.

The pair both took part in Monday's mixed triathlon event, less than 24 hours before an open water training session on Tuesday was cancelled. That was after one of the four samples taken from the Seine on Monday failed to meet standards for the presence of bacteria present in human excrement.

"On the days of the Triathlon competition, the World Triathlon Federation guaranteed that the water quality assessment complied with the defined regulations," read a statement from the COP. "Notwithstanding compliance with the required safety limits, the presence of some of the parameters assessed carries a risk of infection."

Portugual's Olympic Committee went on to say it was "attentive and providing the best health care for its athletes." However, that may not be enough to simmer the frustrations of angry athletes and fans.

The federation also confirmed both athletes are now stable and being monitored at the Olympic Village at present. But the pair are far from being fit to compete following their ordeal.

It was confirmed that Vilaca, 24, was experiencing more severe symptoms than his compatriot. The COP indicated Santos, 29, became ill in the days after Vilaca, but her symptoms were not as serious.

Taking to Instagram stories, Vilaca said: "For non-Portuguese speakers this means I am feeling sick with stomach flu symptoms. Getting the best help from my NOC though."

Despite the setbacks witnessed this summer, the women's 10km marathon event went ahead on Thursday. Sharon van Rouwendaal of the Netherlands clinched gold, while Australia's Moesha Johnson snatched silver and Italian Ginevra Taddeucci took bronze.

The setbacks on the Seine will remind some fans of the poor water conditions also witnessed at the 2016 Rio Olympics. Athletes in Brazil again came down with illness in their pursuit of Olympic glory, with numerous experiencing fevers, vomiting and diarrhoea.