Ryan Lochte

US swimmer Ryan Lochte and three others robbed

Lochte, Gunnar Bentz, Jack Conger and Jimmy Feigen were stopped by people posing as armed police, the US Olympic Committee (USOC) said in a statement.

The robbers demanded money and other personal belongings.

After reports emerged of the incident, the USOC initially denied that Lochte had been robbed.

"All four athletes are safe and co-operating with authorities," the USOC's statement said.

The group had been attending a party at the French Olympic team's hospitality house when their taxi was stopped on the way back to the athletes' village.