Belgium have pulled out of the mixed triathlon in Paris after its Olympic committee says one of its competitors fell ill while swimming in the River Seine.

Uncertainty surrounds the final Olympic triathlon event in Paris because of renewed concerns regarding water quality in city's waterway.

The mixed relay is due to take place on Monday morning but could be pushed back after heavy rain on Wednesday and Thursday again caused levels of bacteria in the water to rise.

For at least one team, a possible delay won't convince them to plunge into the Seine.

Claire Michel, who finished 38th in the women's triathlon on Wednesday, "is unfortunately ill and will have to withdraw from the competition," the Belgian Olympic and Interfederal Committee said in a statement.

The statement did not elaborate on Michel's illness - Belgian media have reported it is E. coli - but it comes after concerns over the river's water quality.

Organisers had said that bacteria levels in the river were at a level that was considered safe for the athletes.

The Belgian committee said it "hopes that lessons will be learned for future triathlon competitions at the Olympic Games".

"We are thinking here of the guarantee of training days, competition days and the competition format, which must be clarified in advance and ensure that there is no uncertainty for the athletes, entourage and supporters."

The men's race was changed from Tuesday to Wednesday, the same day as the women's competition, earlier this week, with athletes unable to swim in the river until the day of the race.

Following a meeting on Saturday evening, a statement was issued by organisers on Sunday morning, which read: "(The) decision has been made to cancel the swim leg of the triathlon familiarisation, which was due to be held on August 4 at 8am.

"Given the heavy rain over the nights of July 31 and August 1, which had been particularly intense upstream of Paris, we still see impact on the water quality in our venue.

"We are expecting an improvement on the conditions in the next hours, but not to a level to which the swim familiarisation planned for (Sunday) can take place."

Speaking at Sunday morning's IOC briefing, Paris 2024 director of communications Anne Descamps added: "We are expecting improvement regarding the weather forecast. As we've seen the sun and the heat have a very positive impact."

Great Britain won gold in the inaugural Olympic mixed relay in Tokyo and will be among the favourites to secure another medal.