Brazil face another embarrassing exit from a tournament on home soil after Neymar slumbered through a second 0-0 draw of Rio 2016 against Iraq.

The Olympic hosts need to beat group leaders Denmark on Wednesday to win to avoid a stunning exit, just two years after their devastating 7-1 World Cup defeat by Germany.

The 84-year-old grandmother of a Thai Olympic bronze medal winner collapsed and died on Monday while celebrating the weightlifter's success in Rio, police said.

U.S. swimming legend Michael Phelps returns Monday to the hunt for more Olympic glory as swimmer Yuliya Efimova opens her campaign to restore Russia's battered pride.

France midfielder Paul Pogba arrived at Manchester United's training base on Monday to complete his record-breaking return to the club from Juventus, an AFP photographer reported.

United States kept their quest for fourth straight women's football gold firmly on track when captain Carli Lloyd ensured a 1-0 victory over France to qualify for the quarter-finals.

Moroccan Olympic boxer Hassan Saada, who has been arrested in Rio for allegedly sexually assaulting two female cleaners, "does not understand the allegations", the Moroccan Boxing Federation said on Saturday.

Officers arrested Saada, 22, from Casablanca, on suspicion of committing the assault on Wednesday, said a police statement released hours before Friday's opening ceremony.

A bullet which tore through the media center of the Olympic equestrian venue on Saturday was not targeting the Games, Rio 2016 organizers said, describing the security scare as an "unfortunate incident."

No one was injured, but a TVNZ report said the bullet narrowly missed a New Zealand team official who was badly shaken by the incident.

Four-time gold medallist Venus Williams, suffering with a virus, slumped to her first ever opening round loss at an Olympic Games on Saturday, joining jet-lagged Agnieszka Radwanska at the exit door.

American fifth seed Williams, the singles champion in 2000 and, at 36, the oldest woman in the draw, lost to Belgium's Kirsten Flipkens 4-6, 6-3, 7-6 (7/5) in a three-hour centre court marathon.

American legend Michael Phelps joins the fray in Rio Sunday hoping to reverse the trend after triumphant Australia dominated the first day's action in the Olympic pool.

Inspired by swimmers Mack Horton and Cate Campbell, Australia surged to the top of the medals table after an intense first day of competition.

It's been a difficult few months for the Olympic women's basketball teams from Turkey and France. Both countries have been victimized by deadly extremist attacks, and Turkey is struggling with the aftermath of a bloody attempted coup.

For players on both teams, being at the Summer Olympics in Rio offers a respite from what's happening at home — and a chance to show the world a united front.