Lochte and three other swimmers initially claimed they were robbed at gunpoint on the way back to the Olympic Village, before CCTV footage emerged of the men vandalising a petrol station after a night out.

They reportedly then argued with a guard who ordered them to pay the costs of their damage.

Brazilian police claim the robbery was a "fabrication".

Two of the other swimmers, Gunnar Bentz and Jack Conger, were prevented from flying out of Brazil and questioned by police over their version of events, before being belatedly allowed to return home.

A fourth, Jimmy Feigen, was briefly detained and has now agreed to donate a sum of nearly $11,000 (£8,400/€10.200) to a Brazilian charity.

The trio claimed in sworn statements that Lochte, who had already left the country, had damaged property and was "in need of calming down" as he argued with an armed security guard.

Bentz has this evening claimed that Lochte pulled a metal advertisement in a frame to the ground, and then "stood up and began to yell at guards" after they were caught.

"I want to apologise for my behaviour last weekend - for not being more careful and candid in how I described the events of that early morning and for my role in taking the focus away from the many athletes fulfilling their dreams of participating in the Olympics," Lochte said on Instagram.

"It's traumatic to be out late with your friends in a foreign country - with a language barrier - and have a stranger point a gun at you and demand money to let you leave....

"I am very proud to represent my country in Olympic competition and this was a situation that could and should have been avoided.

"I accept responsibility for my role in this happening and have learned some valuable lessons."

All four swimmers had won gold medals as part of US relay teams.

Lochte, Bentz and Conger were all part of the 4x200 metres freestyle squad and Feigen participated in the 4x100m freestyle event.

A disciplinary investigation has been opened by the International Olympic Committee but there is little sympathy for the swimmers in either Brazil or the US. 

Rio de Janeiro Mayor Eduardo Paes said this his "only emotion towards them [the swimmers] is pity and contempt".

"It's a shame that they're such weak characters, that they have such personality flaws and it's up to the American Olympic Committee [sic] to sort it out," he added.

More than 1.8 million tweets using the hashtag #Rio2016 had been registered complaining about Lochte, with Rio 2016 communications director Mario Andrada admitting the host nation felt "humiliated".

"The behaviour of these athletes is not acceptable, nor does it represent the values of Team USA or the conduct of the vast majority of its members," said United States Olympic Committee chief executive Scott Blackmun in a statement.

"We will further review the matter, and any potential consequences for the athletes, when we return to the United States. 

"On behalf of the United States Olympic Committee, we apologise to our hosts in Rio and the people of Brazil for this distracting ordeal in the midst of what should rightly be a celebration of excellence."