The down-to-earth 23-year-old held off Canadian teenager Summer McIntosh and American great Ledecky to join Dawn Fraser as the only Australian female swimmer to retain an Olympic crown.

Simone Biles will make her eagerly anticipated first appearance at the Paris Olympics on Sunday while British breaststroke king Adam Peaty aims to emulate Michael Phelps in the swimming pool.

McKeon, who was the star act in Tokyo and is at her last Olympics, won her sixth gold and 12th medal overall.

The 38-year-old effectively ruled himself out of the singles tournament as he battles a thigh injury picked up in training at Roland Garros, the scene of 14 of his 22 Grand Slam triumphs.

For Dressel, 27, it was his eighth gold medal from three Olympics, and he was tearful in the celebrations.

Sheng, who won an individual silver medal at the pandemic-delayed Tokyo Olympics three years ago at the age of 16, and Huang, 17, kept their cool to edge past South Korea's Keum Ji-hyeon and Park Ha-jun 16-12.

Nadal, a singles gold medallist at the 2008 Olympics, is playing in his final Games having also won doubles gold in Rio in 2016, while Djokovic was a bronze medallist in singles in 2008.

Paris Olympics organisers are looking into what led to a pitch invasion during the opening match of the Olympic soccer tournament between Argentina and Morocco, they said on Thursday.

Two-time Olympic gold medallist Andy Murray said he will not compete in the singles competition at the Paris Games and will prioritise the doubles event in the final tournament of his career before retirement.

The Hashimi siblings are the first cyclists - male or female - to represent Afghanistan at the Games.

The Italian said he was "sad and disappointed" to drop out, adding that he had started feeling unwell on Monday after a practice week in Monaco.

France deployed about 1,000 police officers backed by Israel's own internal security service, Shin Bet, to welcome thousands of supporters for the evening kick-off. They cordoned off the streets around the Parc des Princes in western Paris and set up a perimeter a few kilometres away from the stadium

"I can't explain what happened. We spent about an hour and a half in the dressing room where they never told us what was going to happen," Mascherano told reporters.

Former Olympian and current BKSP shooting coach Asif Hossain Khan admitted the harsh reality of Bangladesh’s chances in the Olympics, but he was hopeful that if these athletes can deliver their best individual performance in the meet, they can count their participation differently.

A staff member from the Canadian women's football team has been detained by French authorities for flying a drone over a New Zealand training session ahead of their match at the Paris Olympics.

Around 1,000 French police officers will be on duty on Wednesday to protect Israel's football match against Mali at the Paris Olympics where protests are also expected, Interior Minister Gerald Darmanin said.

The dealers have promised a steady supply of wares, but warned prices may go up and delivery wait times too under the weight of tens of thousands of security forces and heavy demand.

Nadal, the 2008 singles gold medallist, will pair up with Alcaraz in a tennis dream team at Roland Garros, looking to also add to the doubles title he won with close friend Marc Lopez at Rio in 2016.

“Considering the magnitude of the Paris Olympics, my preparation is not good enough,” Sonia told The Daily Star on the eve of her departure to Paris on July 20.

The 37-year-old, a two-time Olympic champion, is planning to play in the singles and doubles at his fifth Games.