US swimmer Ryan Lochte apologises over Rio 'robbery' incident

US swimmer Ryan Lochte has apologised for his behaviour surrounding a late-night incident at a Rio de Janeiro petrol station, saying he should have been more careful and candid about how he described what happened.

Lochte said in a lengthy post on Instagram that he was apologising for his role in taking the focus away from other Olympic athletes.

The 12-time gold medallist reiterated his view that a stranger pointed a gun at him and demanded money to let him leave.

But Lochte said he should have handled himself more responsibly.

Brazilian police have said Lochte lied by saying he and three other swimmers were robbed.

They vandalised a petrol station bathroom and were confronted by security guards, police said.