File photo of Ryan Lochte [Photo: Xinhua]

American swimmer Ryan Lochte apologized on Friday after he was found out fabricating a mugging story during the Rio Olympic Games.

"I want to apologize for my behavior 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," he said on Twitter.

"I should have been much more responsible in how I handled myself, and for that am sorry to my team mates," he said.

Lochte, together with fellow U.S. swimmers Gunnar Bentz, Jack Conger and Jimmy Feigen, are accused of having fabricated a story about being robbed by gunmen posing as policemen.

Surveillance footage and an investigation by Brazilian authorities showed that they had vandalised a gas station bathroom and had handed over money to armed security guards who had prevented them from leaving.

The 32-year-old Lochte, Bentz and Conger have returned to the United States, while Feigen was still in Brazil on Friday morning. Feigen had agreed to pay 11,000 U.S. dollars to a Brazilian charity, police said. His passport would be released upon providing a receipt.